1 Weather, one of the most astonishing forces on Earth. Capable of both devastating power and spectacular beauty. Wherever you live on the planet, weather shapes your world. Yet, for most of us, how it works is a mystery. To really understand weather, you have to get inside it. So, I'm going to strip weather back to basics All in the name of science. . . uncovering its secrets in a series of brave, ambitious and sometimes just plain unlikely experiments Well, it certainly feels like a dust storm from here! . . to show you weather like you've never seen it before. Water lies at the heart of our weather, but not just as rain. Because water can transform itself, redefining its powers in the process, creating the fastest, the slowest, the softest and the hardest weather on Earth. Often changing from one to another with alarming speed and striking consequences. In this programme, I'll reveal water in all its shapes. I'll capture a cloud OK, little cloud, let's see what you've got! . . to see just how much it weighs. Discover why hailstones are able to do so much damage Ooh, look at that! . . find out what would happen if rain fell in one big lump It's amazing, isn't it? . . and I'll experience water in its most ferociously powerful form as an avalanche. I'm speechless, genuinely speechless! All our everyday weather appears to come from the clouds. They're the best clues most of us have as to what the weather is likely to do next. They dictate if it's sunny or dull . . and they're where all our watery weather seems to come from. But how? What exactly is a cloud? Come on, you've done it! If not, you should. Gazing at clouds, dreaming up shapes. And the next time you do, two things you should know about clouds that might just change the way you think. Number one, clouds are really heavy. Even that fluffy little cumulus could weigh as much as two elephants. And secondly, because of that weight, all clouds are falling slowly, steadily down to earth. I know, both those things sound pretty unlikely. Which is why I'm going to put them to the test. And I'm going to start by trying to discover just how much a 'small cloud' really does weigh. Now, I know I'm not the only one who, when presented with a sign on a bench saying 'wet paint', has to touch the bench just to check it really is. So, when I heard that a cloud can weigh as much as two elephants, I had to check it out. The only thing is, it turns out that weighing a cloud is a bit more of a faff than checking to see if paint is wet. Obviously, you can't hang a cloud off a spring balance or pop it on a set of scales, but you could measure the moisture in it and work it out from that. So, I thought, what if we could fly a giant ball of cotton wool into the cloud to gather the moisture? As an idea, it needs a bit of finessing, yes. So, I got an engineering mate of mine to iron out some of the wrinkles, and he came up with this! OK, so it's not actually cotton wool. It's an industrial version - ceramic wool. And it's not one solid ball either. My friend reckoned that by making the centre hollow, it would double the amount of wool that came into contact with the cloud. He calls it his 'sky-sponge'. And then we've got that to put it in the cloud. It's all fairly standard stuff. So, first off, let's check how much this sky-sponge weighs dry. That's 37 kilos, which for a sponge is already pretty heavy. But we need that weight to be able to fly it accurately. Especially when the pilot is someone not that used to carrying freight. I know, I know, it's not a good start. But as nobody has ever done anything like this before, I'm as good a choice as anybody. In the end, it was deemed not a job for an amateur, no matter how enthusiastic, so I took a co-pilot, Andrew, with me to keep an eye on thingsmostly on me. So, helicopter, check. Basket full of highly absorbent ceramic wool, check. All I need now is a nice, little cloud to dip it into. And that's not as easy as you might think. Because when you get close to them, clouds are Well, they're enormous! You look at them from the ground, they all look perfect and fluffy and small. Get up and they look entirely different. I've got to find a nice, individual one, drop it in and see how much water it pulls out again. I'm assuming it won't soak up the entire cloud and we'll be left with underslung the weight of two elephants. That would be bad. A full-grown African elephant weighs, on average, four and a half tonnes. A quarter of that would pull my helicopter straight out the air. But if I just weigh a fraction of a cloud, then multiply my results, it should give us some idea how much a whole cloud actually weighs. Pick a victim. What about the one in front, up here? Yeah, that's a nice one. Right, cloud has been sourced. It is quite important that the helicopter itself doesn't go in the cloud. We have to remain visual with, well, pretty much everything. I need to fly low enough to dip the sky-sponge into the cloud but high enough to keep the chopper above it . . which is trickier than it sounds. 'Well, for me. ' Oh, great, well, that's all round bad. First time round, I miss the cloud altogether. This is a fairly unusual exercise, cloud collecting. Yeah, that's my excuse, anyway. This one will do a treat. OK, little cloud, let's see what you've got. Close up, the cloud seems so wispy, it's hard to imagine we're going to soak any water up at all. OK, we dipped it, let's get this thing down and see what we've got. Well, it's wet, that's a start but how wet? Have we managed to collect enough moisture to make a difference on the scales? We have ten whole kilograms of difference. I know that doesn't sound like much, but look at the size of the cloud. Then look how much of it the sky-sponge flew through. Just that small section had ten kilos of water in it. If every section that size weighs the same, then that little cloud must be getting on for, well, not quite nine tonnesbut a lot. THUNDER BOOMS And a good-sized thunder cloud might be ten kilometres tall and ten kilometres wide . . which would make its total weight more like a million elephants. Or, if you prefer, about 60,000 jumbo jets. So, how on earth does all that weight stay up there? To find that out, we're going to have to build a cloud of our own. Right, what I've asked to achieve here is an indoor cloud. What I've got is a cattle trough full of water and I don't know what these things are. Fortunately, what I've also got is Jim, who is an atmospheric scientist and can hopefully help. What is this? How's it going to work? So, this is how we're going to make something akin to clouds. - Right. - Obviously, it's not a cloud - but it's the closest we've got to a cloud-making machine. - Right. So, what we've got in here are some ultrasonic humidifiers. So, you quite often see these things in garden centres and things like that. - They just produce very, very fine mist. - Garden centres? - Garden centres. - It's just sounding less hi tech now, I'll be honest. They're masquerading as nice, ornamental devices but secretly they're cloud-making devices. Well, there we go. Well, come on then, make it work. So, all we need to do is turn this on. - Oh, hello! - There you go. Suddenly, miniature clouds appear. And that's just breaking the water down into smaller bits? We're breaking the liquid water into very, very tiny droplets of water. These garden pond devices turn the water into tiny droplets, and that is exactly how a cloud works. Clouds float because the water drops inside them are so small and so light. What's the difference in size? How big is a droplet of this compared to a droplet of water? So, a droplet of that is five microns, - but that means absolutely nothing to you. - Small?! OK, but a rain droplet, you can get your head round the size of a rain droplet. A rain droplet is about two millimetres. So the difference in size between these and the rain droplets is the same as if you got a sugar cube and a caravan. Hang on, which is the caravan? So, the caravan is the rain droplet. - Right. - And the sugar cube is these tiny little droplets. Right, well, that is working! The humidifiers have split all our caravans up into billions of sugar cubes. - OK, lid goes on. - OK. 'But to really complete the effect, we want to see 'if we can get those tiny moisture droplets to float in the air. ' We'll turn the fan on now and we'll see our clouds emerge. And there it is! Weirdly, it feels dry. Hard to believe our sky-sponge managed to soak this stuff up. So, this doesn't just look like a cloud, this is pretty close to a cloud. These are just droplets of water, very, very small droplets of water, and that's what a cloud is. Jim, not being critical of your cloud, but it looks a lot more frantic. I think of clouds as just solid state, really, just drifting. What you're seeing here is what's happening around the edge of the cloud, it's constantly changing. - So you get up close to a cloud and it's really quite busy? - Yes. So, whilst I'm very impressed with your home-made cloud here, it's kind of notup enough! Now, this might look like overkill, but actually our cattle trough is surprisingly heavy, just like the water in a real cloud. And I do need to get all that water off the ground to check that second fact. Are all clouds really falling back to earth? Jim and I wait with baited breath. We might have made the water droplets small enough to float but . . it's true, once they're up in the air, they drift back towards the ground. So this effect where I can see it rolling over the top and then sort of falling, that's accurate? Yes, our cloud is dropping out. So, if you look at clouds with binoculars or something like that, you'll see bits of streams of cloud. So, because this is small, it all looks faster, but if this were as big as a real cloud, this effect, this exact effect, is what's going on all of the time. Yes, just continuously all the time. Round the edges of clouds, round the periphery of clouds, you've got this going on all the time. So, there you have it - clouds are heavy and they are all falling slowly down to earth. It's just that most evaporate before they ever get there. In fact, the typical life span of a small cumulus cloud is only ten to 15 minutes. But while they're up there, they act as a sort of a public transport system for water, carrying it from one place to another . . until either the service goes off duty or they dump all their passengers out as rain. There are about 13 trillion tonnes of water being moved around in the atmosphere. And every day, about a tenth of that comes crashing back down to earth. WIND HOWLS Sometimes, these storms are incredibly intense. The quickest on record dumped 12 centimetres of water in just eight minutes. The heaviest managed nearly a metre and a half of rain in under ten hours. And so to my home territory, where, on average, it rains one day out of every three. This is my favourite place in the entire world. It's in the Lake District, Honister Pass, running down to Lake Buttermere. I've been coming here for 27 years. It has one of the best views in the world. I've seen it once. That's because this specific place is the wettest in England. On average, four metres of rain falls here every year. And yet, on the one day when I am here specifically to talk to you about rain, it's not actually raining! We've had to resort to this Yes, sprinklers, in the wettest place in England. However, this will suffice perfectly to allow me to show you what I want to show you. Puddles. Puddles hold the key to seeing how those tiny cloud droplets turn into raindrops. We can't look into a cloud to see how raindrops form but we can get an idea of what's going on by looking in a puddle. As the raindrop hits, part of it is attracted to the water. What bounces back up is a smaller droplet about half the size. When that droplet hits, the same thing happens again, around half of it stays in the puddle. Now, imagine that in reverse and upside down. The puddle is the cloud. A water droplet doubles in size by attracting other water droplets. These stick on in a process scientists call 'coalescence'. It increases again and again until it's so heavy it falls away. And that is, roughly, how rain is formed. It feels right like this - this is how it feels here. Which is just as well, because I've got one more thing I want to tell you before I get them to turn these sprinklers off. And it's about the official difference between rain and drizzle. Look closely at a puddle's surface. If the drops are splashing, like here, then it's rain. But if there are no splashes, then it only qualifies as drizzle, officially. Clever, isn't it? Splashes, rain. No splashes, drizzle. But what they've both got in common is that they are just too heavy to be held aloft. We talk about heavy rain but water is heavy, very heavy! To give us an idea of just how heavy, we are about to see what would happen if all of Borrowdale's four metres of water fell in one go. Obviously, we can't get a digger the size of the Lake District. So, we're just going to recreate what it's like when four metres of water hits one small area. So, we have four cubic metres of water in the bucket, which amounts to four tonnes, at height. Then, beneath it, you'll see we've found a car for scientific purposes. Let's see just how much damage that amount of water can do. Hmmlooks like rain. Yeah, pretty brutal, but I shouldn't be surprised . . because the water actually weighed four times more than the car underneath it. Every minute of every day, 900 million tonnes of rain land on our planet. That's about the same amount of water as in all 16 lakes of the Lake District. Oh, they're going to notice! But it does prove the point - water is really heavy. That is just the annual rainfall for Borrowdale, where I've been going on holiday all of my life. Explains something about it. It is amazing, isn't it? Luckily, this could never happen with real rain. Not even in a tropical storm where sometimes it feels that the heavens have literally opened. Partly because, as we saw earlier, raindrops fall the moment they get heavy enough. And partly because of what happens to rain as it falls. To show you what I mean, I'm hard at work building a sand castle . . and Professor Jane Rickson from Cranfield University is filling a plastic bucket from a pond. There were always kids like you on the beach, weren't there? OK, so what's all this about? Well, pour water on a sand castle and you completely flatten it. No surprises there. But rain doesn't fall from waist height. It falls from clouds that are at least 300 metres above the ground. And that makes all the difference. Let me show you, by building another sand castle and throwing the water off something just a little bit higher. Now, obviously, this isn't as high as a real cloud. They start at around 300 metres. This tower is 30, but it's tall enough for what we want to do. OK, Richard, let it go! Idiot! Yeah, wrong side. How was I to know? Let's try it again. OK, Richard, let it fall! And so another bucketful leaves the tower but what arrives below is rain. And there it is, it's still standing. So why is it if I throw the water from up there? You'd think it would smash it to bits even more, but it's still standing. What's the difference? Well, what happens, as you were throwing that water down, air resistance, the turbulence in the air is overcoming the surface tension of that lump of water, breaking it into smaller drops. Do you want to go and see that? Shall we do it again? YesI'll get the water. As the water falls, it meets air resistance, and the larger the lump of water, the more resistance it experiences. That friction breaks the water up into smaller pieces, sometimes inflating the drops like parachutes, before blowing them apart. The further they fall, the smaller those drops become, until finally they're so small that air has little effect on them and they land as rain. So, that's why the water landed in drops and didn't smash it, rather than a big bucket-shaped lump? That's right, and in fact you can actually see the point at which that lump starts to break up into those smaller drops. Well, you can if I climb the tower again. It actually happens surprisingly quickly. Within ten metres, there is enough air blowing on our bucketful of water to break it down into drops. If our digger had been just a few metres higher, then the car might well have survived. So, even if it was possible for water to fall out of the sky in one big lump, by the time it got to the ground, it would still be rain. Because they break down like this, the average raindrop ends up about two millimetres across. But there is a way that water can fall out of the air in bigger, more dangerous pieces. By shape-shiftinginto ice. Now, most of us think that when we see ice falling out of the sky, it's hail. So, what if I told you this wasn't hail at all. Sure, it looks like hail but it can't be hail. You can't get hail in winter, it only happens in summer. I know, you think you've seen hail in winter, but trust me, you haven't. What you've seen is this an ice pellet. Ice pellets are formed when a snowflake partially melts on the way down, losing all its pretty branches. It then refreezes, forming a small ball before it hits the ground. Just to make things even more confusing, in North America, they call this sleet, which over here means a sort of slushy mix of rain and snow. Either way, this is not hail. Hail is something entirely different. Charles Knight has been studying hailstones for the last 50 years. And in his refrigerated laboratory, in Boulder, Colorado, he offers to show me exactly how hailstones are different by sawing one in half. It's very simple, we just use a hobby band saw like this. - You're just going to slice it in half? - Yes. How long have you had that hailstone? Oh, about ten years, actually. What?! But it's worth it. As soon as Charles opens it up, the difference is revealed. Hail is made of layers. There, you can see one layer there, anyway. So where there's that little circle? Yes. On the bigger hailstones, there's much more obvious layering. This is an example of really what you would call a giant hailstone. - It's enormous! - It's enormous, yes. But that's obviously not going to stop him cutting it in half, even though this one is 15 years old. Oh, wow! This time, the layers are crystal clear. If you make a thin section, then you can really see the layering. It's a slice right through it, that's absolutely beautiful! That's really telling its own story, isn't it? Just like the rings of a tree, these layers chart the story of how this hailstone grew. It's a story that starts THUNDER CRACKS . . with a thunderstorm. And thunderstorms only tend to happen in summer. Because of the height of thunder clouds, some of the water droplets inside them freeze. But the powerful updraughts created by the warm weather keep the droplets supported in the cloud where they collect more water, with new layers freezing on in a separate shell. Until, finally, there are so many layers that they're too heavy to be supported and they fall to the ground. Which got me thinking. Because it's made in layers, does that mean hail is stronger than a single, solid ball of ice? You make wood stronger by laminating it. You make glass stronger by laminating it. So, does laminating ice make it stronger? Certainly, hail is powerful. It causes over テつ」1 billion worth of damage a year. But is it any harder than conventional ice? To find out, we're going to have to go into uncharted territory, with an experiment that hasn't been done before, using that. Yeah, I know, it looks like a lump of plastic pipe on some tables, in a field, and to some extent, well, it is. But you should see what it's about to do to that table tennis bat. Its inventors, Purdue University's Jim Stratton and Craig Zehrung, wanted to see just how fast they could get an ordinary ping pong ball to fly. And the answer, using this contraption, turns out to be very fast indeed. That is astonishing! This projectile is moving when it comes out of there. Oh, yeah. About 919 miles an hour. - That's brisk, isn't it? - Yeah. So, you brought along your device which, if you think about it, is a sort of nightmarish serving machine, and you've agreed to help us? Mm-hm, yeah! OK, right, so here's the plan. We're going to see which is harder, ice or hail. But first of all, we've got to make some hailstones. We've already seen how much of a faff that is, even for Mother Nature . . but luckily, Jim and Craig have a plan. A plan that starts with dry ice. It's like an '80s pop video! A pop video starringa bead on a bit of string. The dry ice makes the bead really, really cold - Two roles? - Yup. . . before it's dropped into cold water. You'll notice every time he puts it in there, you can hear a little bit of a crack, you can hear a little bit of a fizz. That's the water instantaneously freezing to the outside. So that's one layer of ice round that little seed? Very small layer. How long does this take? Erm, about ten minutes. - Oh, God! - How many of these do we need? - Quite a few. 'And they need to be the size of ping pong balls to fire them 'from Jim and Craig's gun. ' - Can I have a go? - Yeah! Right, dip it in here . . fairly quickly into there. That's it! Look at that! It's already the size of apea. I'm just suggesting, we probably need to find a way of mass-producing these. I mean, this is the land of Henry Ford. Right! One is good, we could try three. - Erm - And now you've tripled your efficiency. Haven't I, haven't I? Sometimes on TV, we don't do things in actual time. This is one of those occasions. You going to do anything? I'm reading this. There's no words, you're looking at the pictures! - It's my turn again? - Yes! Whoo-hoo, you've been busy! Hail's ready! - They're done! - They are done! Magnificent they are as well. Look at that. OK, they might need a little bit of rounding off to get them down the barrel of the gun, but the size is good. Say goodbye. - One - Excellent! - . . two. - 'Three of 30. ' We're going to have to do some more, aren't we? We are, yeah. A whole bunch, yeah. So we have something to compare them with, we've also frozen some water into ordinary ice, using a few of Craig and Jim's spare ping pong balls as moulds. So, we've got solid ice and we've got hail, which is ice in layers. Time to put them up against each other to see if there really is a difference. And we can't resist starting with one of our home-made hailstones. I'll give you the honours. All you have to do is puncture it. Scoot back a little bit so we can look at the Why is everybody else standing back? - Well, we're getting somewhere we can see. - Right. - Ahhh - LAUGHTER What?! I've not done this before, have I? How wrong can it go? Are we ready? Yup, we're ready. Punching a hole in there now. Oh, it's quite dramatic, as it turns out! Yeah! Let's have a look at the footage. Believe it or not, we're breaking new scientific ground here. So, to make sure we capture any differences between the ice and the hail, we're recording everything at ultra high speed. And sure enough, our cameras capture every detail, from the plastic seal popping off the tube, to our hurtling hailstone punching through the target. - Look at that! - That is awesome. Beautiful. Is it worth experimenting now with just seeing how much more resilient one is than the other? Yeah, we've brought plenty of materials we can shoot at. We can actually shoot two at the same thing and see what one will and won't go through and the type of force that we have in them. That's exactly what I was meaning Do that. - All right. - Let's do it! So, here's the set-up. We've got lots of different sorts of wood and we're going to take two shots at each piece. First, with plain ice, then with our home-made hail. First up, chipboard. Right, three, two, one! Ice, straight through. Hail, straight through. OK, slightly thicker piece of chipboard. Same result. Plywood. The ice barely dents it. Come on, hail! Three, two, one! Well, there is a difference. The hail splintered the back of the plywood. Let's try a slightly thinner piece. This time, the ice barely makes it through. The hole it makes is far smaller than the projectile itself. Right, fingers crossed. Ooh, nice! Awesome! - Did it work? What happened? - It did! It smashed and there's your impact. - That's right the way through. - Yup! In fact, that's completely different. Same piece of wood, same shooting speed, different results. In slow-mo, you can clearly see how much of the ice ball never makes it through the board. Well, it might be crude, but that is what I'd hope we'd see. This mark here, that's from the straight ice, barely getting through. That is our home-made hail with its laminated layers around it. Clearly a more fearsome projectile. Both balls are made of frozen water, so you wouldn't expect any difference in how hard they are. But the layers in hail do appear to make it stronger. So summer hail does seem to be harder than winter ice. But water can shape-shift into something even more dangerous . . naturally quicker than hail, with a mightier punch than hail. And what it is might well surprise you. This is how most of us are used to seeing snow move. Delicate flakes floating gently down to earth. Floating so gently that a snowflake can take nearly an hour before it finally reaches the ground. Travelling at just four miles an hour, little more than walking speed. And yet snow can be the fastest form of water that there is. RUMBLING Because when it's in an avalanche, it can hit 80 miles an hour in six seconds flat. And then, well, it just keeps on accelerating. The fastest one ever recorded, on Mount St Helens in America, clocked a staggering 250 miles an hour. So how can snow move down a mountain faster than water can? Walter Steinkogler, of The Institute for Snow and Avalanche Research, is trying to find out how that incredible speed is possible . . by starting an avalanche of his own. - Walter. - Yes. Is this where it's going to happen? Yes, absolutely. You can see it quite nicely now. That's the whole slope. You see two spontaneous avalanches already and we're going to try to release the avalanches from the very top. Don't those two avalanches mean it's already happened? No, no, no, not at all, you see there's plenty of snow still on the slope and actually this is a really good indicator that there is the potential to produce nice avalanche. - When that's going on, you're going to be conducting experiments and learning. - Yes. This is part of an ongoing piece of work for you, isn't it? It is, it's actually my part of my PhD thesis, - and this data is really essential for my work, yes. - Right. There are several different types of avalanche, but the fastest by far is what's known as a 'dry powder avalanche'. And that's the type we're hoping to get. If he can trigger a dry powder avalanche, Walter can find out more about how they move so fast, and we've offered to help by putting a barrage of slow motion cameras on the slope. We're not going to mess with your PhD? I will tell you afterwards, but I would appreciate it if you don't. I won't. If I do, send him the bill. - I send to this guy? - Graham. - Perfect. He's in charge, I'm not. Let's hope it doesn't come to that. But I would like to add an extra element into his experiment. So, Walter, can I place these on the slope? If they're a known distance apart, I thought I could time when the front, the head Yes, we call it the 'front'. . . the front of the avalanche passes one of these, I can time it over that distance and I can work out how fast it's going. Sure, that's a nice approach. You can do that, yeah. Thank you very much. Right, we'll do it. Erm, I just need a helicopter. OK, well, that's that sorted, but now we need to work out how to fly our fences into precise positions without triggering an avalanche ourselves. Our safety team have been thinking long and hard about the best way to do it. And what they've come up with is dangling someone on a bit of rope. This someone, in fact, who apparently enjoys this kind of thing. That is the single coolest thing I have ever witnessed. That man is, without a doubt, the best helicopter pilot I've ever seen in action. I mean, that sky-sponge was difficult enough. Just to be flying that close to mountains and sheer rock faces in this gusty, windy, changeable weather. Just that, let alone with another bloke dangling from a piece of rope below you, and then below that, a huge, well, basically wooden sail. I'm speechless! Genuinely speechless! Walter has told us where he expects the avalanche to fall. So we position the first fence slap bang in its path. But the conditions up here are very changeable . . as we discover when we try to fly the second fence in. Suddenly, the winds quicken and start to gust alarmingly. At any moment, the whole fence could be dashed into the side of the mountain, taking that bloke with it . . not to mention the helicopter. And the fence needs to be exactly 100 metres from the first one. Never have the words 'rather him than me' been more directly applicable. It's down. So, everything is now in place. My two boards, I know, are 100 metres apart. When the front of the avalanche passes the first one, I'll start the stopwatch on my phone, stop it when it passes the second and we'll get an idea of the speed. And I do know we're going to be surprised at how something that a little snowflake that can take an hour to drift down out of the sky can suddenly be part of something so fast and so powerful. All we have to do now is wait for them to trigger it. THEY SPEAK GERMAN LOUD EXPLOSION LOUD EXPLOSION LOUD EXPLOSION LOUD EXPLOSION That obviously is the explosives. RUMBLING OK, we're off. Fence one. Fence two. Oh! Well, my boards have gone I missed it. But I suppose it does prove, in a way, just how fast an avalanche can be. And luckily for me, our slow-motion cameras captured everything. So, let's take a look at that avalanche again. This is the moment the dynamite is dropped from the helicopter, causing this explosion at the top of the mountain. Immediately, it's surrounded by a powder cloud, made up of 1% snow and 99% air. This is a dry powder avalanche. The avalanche accelerates down the steep incline until it reaches our first fence. Though not exactly at the angle we expected. The leading edge passes the first one now. And that particular bit of snow reaches the second fencenow. Almost exactly the same time the first fence is destroyed. No wonder I had trouble timing it. Our avalanche was actually only travelling at 25 miles an hour, just a tenth of the speed of the fastest one ever measured. But still faster than if we'd just pushed that snow over a cliff. I want to know how that's possible. Let's imagine there's a chunk of snow at the top and then is starts to move. What's happening to that snow from the moment it starts to move down? Well, first, it will break into pieces and it gets rounded a bit and it also gets compressed. And these are the pieces which you can see up there, they look like snow balls? Technically, most of them they are snowballs, yes. These snowballs are the secret of what's going on underneath that powder cloud. Walter offers to show me how. OK, Walter, this is like an avalanche, how? Well, you imagine an avalanche is moving down a slope, it's going to pick up snow like you're doing now and it's going to put it in motion, as in our tumbler here. It seems you're losing your motivation, come on! Keep on going, one more, you can do it, you can do it! Come on, Richard! Perfect, I think we're good there. You can see already it's compacting, that it's breaking apart again, that it's compacting again. And at some point, you will end up with ball-shaped features. It is magically making snowballs, a cement mixer full of snowballs. We make snowballs. Of course, in an avalanche, this is happening much faster and it's a much more violent process going on there. But this is a slowed-down version of exactly the same process and you can see that kind of grinding, rolling motion - that you can imagine happening in an avalanche. - Perfect. That's exactly the case, true. So, understanding this will allow you to understand more about how fast it might go, where it might go, how it will behave? Absolutely. I would say they are quite done, yeah, yeah. - Turn it off? - Yes, turn it off, please. So in here, snowballs. Perfect snowballs, right? Aren't they? I mean, that's seriously packed. It's quite hard, right? I mean, it wouldn't be that nice to throw it at a person. Are you looking over there and thinking targets? Cos I was. Those cross-country runners? Come on, do it, do it! He was scared for a second. Did you see? Walter wants to excavate the avalanche to see how much snow it contained, and I follow him into, well, a big hole, because I want to be sure whether it's these snowballs that make the avalanche move so fast. This is not easy to answer because it's still ongoing research. But, for sure, it defines the motion of the avalanche. So, you can't say for definite yet as scientists, and I love it when you guys can't give a definitive answer Yes, I cannot, because it's my research. And if I say it now I mean, I have to publish this stuff first. So would you ever end up with your avalanche effectively rolling along on ball bearings? Or like when they used to build they'd get a huge stone and move it to one place to put it up as a monument, they'd roll it along on logs, wouldn't they? Is it like that? I think you can kind of say it like that, yeah. From a scientific point of view, I'm not 100% sure. - You think that's rubbish don't you? - No, no, no. Be honest! Come on, you're being all like scientific just say it's rubbish! No, there are studies that say that really it's the ratio between the bigger grains or the bigger balls to the smaller balls that can significantly influence the speed and the motion of the avalanche. So, you're not that far off, actually. - You're just jealous because it was my idea. - Yes, but, you know You can publish that, actually, it would be something for you. Would I have to write it up? Yeah, but you could do research. I can't be bothered, it'll take ages, you can have it, it's yours. Put something on wheels and it can accelerate quicker than if you simply drop it. And these snowballs may be the wheels of a dry powder avalanche. Snow is the softest, lightest way that water can fall to earth. But an avalanche can move faster than any other type of water. Four times faster than the fastest flash flood ever measured, and it seems snowballs might well be the secret. Of all the water on our blue planet, only a tiny fraction is actually in the atmosphere. Yet water's incredible powers of transformation mean that that's enough to bring us all our clouds, rain, hail and snow . . and with it, all the everyday weather on Earth. In the final episode, I investigate the one thing that drives all our weather temperature. I discover how you can be struck by lightning but you can also be hit by thunder. - BOOM - Ohhh! I witness the mystery of an ice storm. This is strangely addictive! And I start my very own dust storm I hope I don't trigger an international incident! . . to find out how it's possible for sand to travel halfway round the globe. Seriously, it's gone! You can find out more about Wild Weather with The Open University's free wall poster. Call 0845 030 3045 or go to . . and follow the links to The Open University.
Amanda Hammond
Weather. One of the most astonishing forces on earth. Capable of both devastating power and spectacular beauty. Wherever you live on the planet, weather shapes your world. Yet for most of us, how it works is a mystery. To really understand weather, you have to get inside it. So I'm going to strip weather back to basics. All in the name of science. 'Uncovering its secrets in a series of brave '. . ambitious 'and sometimes just plain unlikely experiments. ' Well, it certainly feels like a dust storm from here. 'To show you weather like you've never seen it before. ' There is a powerful invisible force that moves around us almost unnoticed. A force that drives almost all the extreme weather on our planet. That force is wind. WIND HOWLS 'In this programme, I'll discover 'how wind creates that extreme weather. 'What it's capable of 'and just how fast it can go. ' Whoa! 'Along the way I'll attempt to measure the speed of a tornado, 'right next to the ground' Oh! That's huge! 'I'll create a whirlwind made of fire to discover how a wind 'becomes a spinning wind. 'And I'll become one of the few people in history 'to deliberately walk into the middle of a twister. ' I'm going in. This is said to be the place with the worst weather in the world. A place so forbidding that only the fearless or the foolhardy would want to experience it. So, hazard a guess where we're starting. This is Mount Washington, in the unlikely location of New Hampshire, USA. You wouldn't expect extreme weather to be found in New England but on April 12th, 1934, Mount Washington weather station measured one of the fastest wind speeds ever recorded on land. 231mph. In fact, winds here hit hurricane force more than 100 days a year. Now, bear that in mind during the next couple of minutes. Because I'm about to take a little walk outside. OK, just popping out. Which is, it turns out, quite a chore out here. I can not only hear the wind around this building, I can feel it. The whole place is vibrating. Oh, no! I've forgotten my goggles. This is This is the Do it in the wrong order and you just, right, your eyeballs can freeze, any exposed skin, you'll have frostbite on it within two or three minutes. Right that's my best hat, I won't get cold with that on. This is to stop my nose falling off, which would be bad because I'd never be able to wear sunglasses again and I want to. Liner gloves. Mittens. OK. Obviously, I am now obliged by law to say, 'I'm going outside. I might be some time. ' I mean, that's how cold it is indoors! At this point, I think I should try and give you some idea of what I might be in for with a small demonstration. The lightest wind you can feel on your face is about 5mph. Enough to rustle this newspaper. 15mph and your umbrella gives up the ghost. 25mph can cause a deckchair to set sail. Followed at 30mph by your garden furniture. 45 and all hell starts to break loose. Seemingly rigid structures suddenly make a break for it. And at 55mph even small buildings are on the move. So, why am I telling you all this? Because on Mount Washington, it's currently 65. With gusts reaching a staggering 85mph. Believe it or not, I'm actually sheltered at the moment. There's hardly any wind right here because I'm in the lee of the building. It starts about six feet that way and then there's a lot of it and the only way to demonstrate it is I'm going to go and stand in it. And for reasons best known to themselves, Brendan and Sean, on camera and sound, have decided to come with me because they're idiots. So, here we go, right, walking. Not windy, not windy Getting windy This is about 65, maybe 70mph worth of wind, but don't forget this is the site of one of the highest wind speeds ever recorded by man, 231mph. How must that feel? I'd be gone! They do a calculation around these parts where you take your weight in pounds, I don't know what I am, it's about 150, 160. Halve it, that's the wind speed at which you're going to get into trouble, which is about this wind speed. There are three major storm systems that meet right here, sort of long-distance weather patterns, and that corner behind me is the most exposed place. Which should make that the windiest spot on this whole mountain. But lots of places have storm systems. Why is it here that's so windy? Don't worry about this, they said it was just a precaution. So, take my hat, the one that caused this in the first place. Let's pretend this is Mount Washington, this desk fan is the wind and we can see the wind hitting the top of the mountain Mount Washington is the highest thing for miles around. So, although there are hills here and here, and a town here and a ski-resort there they make no difference to the wind hitting Mount Washington, they're not high enough as obstacles to block it or disrupt its flow. So, any wind there is just will hit the top of the mountain. But there's another reason why it's so windy up there and it's complicated enough to demand a clipboard. All our weather happens in the troposphere the first 11 miles or so of our atmosphere. And the top of that layer acts as a sort of ceiling. You know what it's like when you squeeze the end of a garden hose and the water comes out more powerfully and quickly because it's squeezed through a narrower gap. It's exactly the same here. Lose this. It's a precaution. The wind is forced through the gap between the top of the mountain and the top of the troposphere. That's a narrower gap so it speeds up and that's why it always tends to be windy at the top of a hill. So, wind is just air rushing from one place to another. Speeding up as it goes through narrow gaps, slowing down as it hits obstacles. There are winds near the ground that blow locally and ones high in the air that can blow long distances. And that is information you can use to your advantage. Right. Here's how to amaze your friends. First stand with the wind at your back. Then you're looking for clouds. If those clouds are moving overhead directly away from you, or directly towards you, or they're stationary, then the weather is going to stay broadly the same. If they're moving from left to right it's going to get worse. If they're moving from right to left it's going to improve. So, right to left, better, left to right, worse. Straight down the middle stays the same. As long as you have your back to the wind. Unless you're in the Southern Hemisphere in which case you reverse that bit. It's brilliant, isn't it? Really clever. I mean, it's not 100% foolproof because weather is really complicated but it works more often than not and that's about as much as you can say of any form of weather forecasting, isn't it? And the clouds must have been travelling right to left up on Mount Washington . . because the next morning is truly spectacular. Unusually for this time of year, the cloud lifts and the wind subsides slightly. And I venture back outside into a suddenly magical landscape. Folks around here quite proudly proclaim that it has the worst weather in the world. And, well, I don't know. I mean, severe, yes, but looking at it like this, worst, I'm not so sure. But there's no doubt that this is a place shaped by wind. It's so windy here that the buildings have to be chained down. Even the ice appears to fly off in frozen streamers. These streamers don't point away from the wind. They grow towards it. And here's how. Ice crystals are carried through the air by the wind. But the moment they touch an object, they freeze tight. The next ice crystal to be blown in freezes to the first . . gradually building outwards in the direction they blew in from. And that gives me an idea. I've thought of another way you can see wind. I looked around and a lot of the snow that I can see in the air isn't falling, it's being blown by the wind, sticking to any available surface. So, I've got a pocket full of this biodegradable confetti. Let's wait for a good gust. Watch how the confetti blows in swirling patterns. You'd think that at these wind speeds everything would just get whisked away in a perfectly straight line, but it doesn't. It rolls and curls like waves crashing onto a beach. And occasionally, those rolling eddies turn in to tightly knit spirals . . in a shape scientists call a vortex. It's a shape that's crucial to our story. Because almost all the weather we think of as extreme is based around them. This isn't just about strong winds, it's about the other types of weather that wind can produce. Dust devils water spouts tornadoes. All are spinning winds based on this vortex pattern. Even hurricanes and cyclones have the same spiral shape. But to see how those spirals come about, I'm going to examine perhaps the most unusual vortex of them all. It's called a fire whirl. And because they're made entirely of flames, it's easier to see the twisting structure. Right here is where I'm most likely to find one. The tinder-dry forests of Western Australia. The vegetation here is so flammable that any stray match or lightning strike can have it ablaze in seconds. There are 50,000 bush fires a year in Australia and almost any one of them is capable of creating a fire whirl. But because the fires are so impenetrable and because fire whirls tend to be so short-lived, it's very rare to actually see one. Which is why the best way to examine a fire whirl is to build one. But I'm not going to set about building a fire whirl on my own, which is why I have brought two of the world's leading authorities on fire whirls over from Japan to help. Doctor Kazunori Kuwana and engineer Kozo Sekimoto have spent many years looking at how, and why, fire whirls spin. And they've agreed to lend us a hand to try and start our very own fire whirl. But I've just discovered this is the first time they've built a full scale one. Which is a worry. Especially when I see them messing about with baking tins. Of course, we have the fire authorities on hand. But at the moment they look like they are just there to help with the washing up. Time to find out what's going on. Chaps. Baking tins. I'm intrigued. How does this work? We are trying to create a fire whirl on top of the baking pans. We put heptane, a combustible liquid, in the pans. Heptane. Is that what that is? This is water. You know that doesn't burn, don't you, at all? Right. We put heptane on top of the water layer. I knew that. OK. Why are they arranged in this L configuration? If the fire, the shape of fire is entirely symmetric, swirling motion wouldn't occur. So, we need some kind of trigger to create a swirling motion. This shape, this asymmetry somehow triggers something that we're going to see? Exactly. Good. Will it ultimately get rid of these flies? Because Aargh! I see why you are wearing these nets. I thought you were bee keepers when I arrived. It is unimaginably unpleasant. But this isn't merely an extreme type of pest control. We are going to see if these 30 baking tins can help us create a spinning vortex. And we are not just looking for this vortex effect here, we're also going to be looking from up there. We need a bird's-eye view if we are going to reveal what makes a wind spin. And this remote controlled copter is the perfect way to get it. That is why I've brought that guy. That guy is the drone's pilot, Hai Tran, a man with 25 years' experience of flying remote cameras. I pop over to brief him on what we're after. Right, so, if we get a fire whirl going out there, this spinning vortex, I need a shot directly over the top of it, as it forms, you there looking down, we'll get the circle. Just there like that. Right, so you want me to fly over a tornado that is breathing fire? You have used very emotive language there. I mean, essentially, yes. Yes. - OK. - I mean, yes. I think we are going to give problems there with all the wind and the heat that is coming off the fire. I think carbon fibre is pretty durable but the propellers are plastic so they'll probably melt off, at some stage. So, how will you know if that starts happening. It'll warn you? Because, presumably, if you get close and you hit the wind you'll see it go all jiggly and you can go higher? Er, no, these things are stabilised so, the first thing we will see is the copter heading towards the fire. So, the stabiliser will cancel out any effect of the heat - until it melts? - Yes. Turn the stabiliser off. Well Go in raw! Yeah, OK, erm You can tell your friends, 'No stabiliser and I flew it into the fiery tornado thing. ' - We are talking about what, 160km winds? - Yeah. Yeah, no. No. 'I try to explain to Hai why fire is important to this whole story. ' Because heat can create winds. Let me demonstrate with this cooker. Now, imagine the hobs represent the earth being heated up by the sun. Hot air rises off the hob just as it does from the hot ground, making the air above the flames less dense, and therefore, lower pressure. But the cold air around the oven is still at normal pressure so it rushes in to fill the gap, turning these children's windmills. And we can prove that the air is rushing towards the flames with the smoke from this match. Higher pressure air rushing towards lower pressure air. That is the basis of wind. Using flames only accentuates the effect, which is why a massive fire is the best way to create our own extreme wind. But it still doesn't tell us how that extreme wind can start spinning. That is why we need the drone. So, here's the plan. First, we get a flammable liquid called heptane and fill the pans with it. Once they're all full, we'll set light to them. If Kazu and Kozo are right, their L shape arrangement will spontaneously trigger a fire whirl. Next, we'll introduce some coloured smoke to see if our eye-in-the-sky can capture the wind patterns at work. Right, let's give it a go. Time to stand well back. At first, it all seems a bit underwhelming. It looks, well, it looks like 30 baking tins on fire. But as cold air rushes in, it feeds the flames. And then, quite suddenly, they begin to spin. There it is. The spin seems to intensify the fire even more. The flames grow higher. And higher, until they tower above us. It's massive! A real-life fire whirlwind. And it seems that Hai is prepared to give it a go after all. Climbing 20. Roger that. If he can get close enough then we've a chance of seeing how a fire whirl actually works. There's a bit of turbulence up there. Yeah, roger that. Remember they have no way of seeing that turbulence. I think we are getting a bit close to the fire, Sam. He won't know he is in trouble until the controls stop responding and the copter literally melts out of the air. That's looking great, mate. OK, so, now for the tricky bit. Trying to see how our fire whirlwind was formed. Just like we did with the cooker, we're going to introduce some smoke. The crosswind is so strong that the smoke stays close to the ground and, on the far side, it blows in a pretty straight line. But on this side, parts of it bend round the L-shape and get sucked in towards it. Let me try and explain what's happening here. Here's our L. And when the wind comes from this direction, it rolls around the end of it here, and it's drawn towards this fire, but it's also drawn towards this one here and that sets it spinning, that starts our vortex. The vortex rolls along the long arm of the L and when it gets to the fire here, it intensifies. And that is where our fire whirl is formed. The cold air carrying the smoke on the inside of the L is being pulled in two directions at once. And it's that that creates those little spinning swirls of green smoke. And, ultimately, the fire whirl our team managed to successfully capture on camera. Now, obviously you don't generally find baking pans in the wild. But natural Ls occur when two separate fire-fronts meet. Each creating their own opposing winds. And that's also pretty much how other types of spinning weather start. Two or more winds meeting at different angles and speeds, some rising warm air and cold air rushing in to fill the gap. Just those simple ingredients can produce some of the most extreme forms of weather we have. Including the most powerful and deadly wind of them all - the tornado. Because a tornado is spinning, it can move far faster than a normal wind. Not in a straight line, but in the speed that they can spin. And it's that spin that does the damage. Look at it this way. If I'm spinning this bucket around my head, it not how fast I'm walking towards you that dictates how hard it will hit you when I get there. Even if I walk really quickly, that's speed's irrelevant. It's how fast I am spinning the bucket that matters, and what's in it to add to the weight, and that's how it is with a tornado. Debris does most of the damage. That's the weight in the bucket. The most destructive force of the tornado itself is its spin, its rotational speed. Which is why it is remarkable that's the part of the tornado we know the least about. I'd like to find out why. And who better to ask than the Centre for Severe Weather Research in Boulder, Colorado? I make an appointment with its president, Josh Wurman, to ask him why that spin speed is still such a mystery. Scientists have gotten very good at measuring the winds above the ground in the tornado, maybe from 50 metres above the ground up to a couple of kilometres. But the strongest winds in the tornado are below that. We think the strongest winds in the tornado might even be below ten metres. Using remote sensing with radars we can get up close, we can scan back and forth but unfortunately objects block us. There's debris, pieces of houses, cows, whatever, flying around in the tornado, and that is the one place where we are the most blind. Why isn't there just a machine that you can point at a tornado and measure it? I mean, it is moving past, why can't you just measure it? There are two main challenges with in situ measurements. The first is how to get something inside a tornado. The tornado is moving down the fields and we don't know exactly how it's going, it is an unpredictable path. So, getting something in front is very, very hard. Challenge number two is what happens when we succeed, and that is the tornado runs over the object and destroys it, so, unfortunately, the place that we most need to know about is the place that it is hardest for us to see. If we can understand that better then engineers will be able to build better buildings, we'll be able to have better shelters, and fewer people will get injured and die in tornadoes. But how would you begin to measure the speed of a tornado right next to the ground? To try and find that out, we must travel another 1,300 miles, to the distinctly un-tornado-like landscape of London, Ontario. And one remarkable building. I'm going to do something a person wouldn't normally do. I'm going in. This is the heart! I'm in! This is it. I'm in the eye of it. All I can say is, yes, this feels as amazing as I suspect it looks. I am in a tornado, it is the most astonishing feeling, it is dizzying. The world is roaring past and spinning round me but I am still. This is massively scaled down, of course. A real one would be, maybe 100 times bigger and the wind moving maybe four or five times faster but, nevertheless, you get a sense of the relentless, terrifying power of one of these things in the wild. That is the most daunting sight. I've got goose bumps and not just because it is cold in here. I can feel the edges of it, I can feel it moving. It is like I am touching its flanks. It is a living breathing thing. It's a living, breathing, furious thing. This is the Wind Engineering, Energy and Environment Research Institute or WindEEE for short. And it's the only place on the planet capable of duplicating the real-life dynamics of a tornado. It does it by using 106 giant fans hidden behind the walls and ceiling of the world's first hexagonal wind tunnel. The whole structure cost 23 million. And it isn't even officially open yet. We're pretty much the first visitors to set foot inside. Which makes it all the more delicate asking it's boss, Professor Horia Hangan, for a little favour. Just while we're here in this facility, I'd really like to just have a little look at velocities, sort of, that way in tornadoes. Can we have a Let's experiment, a bit, with it. Do you mind if we make a bit of a mess? Not a massive mess. There might be We'll sweep up. You won't know we've been here, everything will be gone. That's fine. We can do a little bit of a mess here. So, we are prepared to catch some stuff that you throw into it, so - It might happen. Thank you. - You're welcome. Good for him. He's trusting us with his 23 million baby. Right. Plan. They really have let me play, sorry, experiment with this incredible installation and I want to look more into velocity, see how fast the wind is moving. If I introduce these ping pong balls into our tornado, I can measure the speed. I'm going to feed them to it. Go! Rise! We think of tornadoes as sucking up everything in their path. Turns out, it's not that easy. I retreat to the control room where the professor and I spend the next four hours trying to get something, anything, to actually fly inside the tornado. With no luck. And then I think of the confetti on Mount Washington. What we need is something flat and light. We find these pink foam squares. They're similar to the confetti but because they're substantially bigger it should be easier to track their progress. If we can get those foam squares trapped in the tornado and if we can get them lifted up and spun round without being spat out then we might be able to time how long it takes one to do a full lap. That is a lot of ifs, I know, but fingers crossed. We are going to start the fans. You see? There it is. - Looking good. - Yeah. Yeah! That's fantastic. There it is, it's exactly what we wanted. So, they're held in. OK, now we've got the foam squares circling successfully, it's time to turn on the tracking technology. The computer follows individual squares, one after another. So, it can create an average speed from the different trajectories. And it works. According to the computer, it's spinning at a shade over 22mph. The first time one has ever been measured this near the ground. Now, obviously a real tornado is about 100 times bigger, and much, much faster. But now we know we can fly things in a fake tornado, it stands to reason we can get them fly inside a real one. The problem is how are we going to get them in there? I am not standing next to it with a bucket. I have tried some things. None of them really worked. I need help with this. So, I have made contact with a scientist who says he might have a solution. He's asked me to meet him here, in, well, as it turns out, the middle of nowhere. This bizarre vehicle is the Dominator Three. A hand-built, tornado-proof armoured car. And as meteorologist Reed Timer explains, it's one of a kind. There's no other vehicle like this. Just one big meteorological instrument. It's like a mobile tornado probe. - Has it ever been in the base of a tornado? - This has. This is the Dominator 3, so this is brand-new. Last year we intercepted three or four tornadoes. What happened to Dominators One and Two? Gone? Oh, no! They're still, they're still on the ground, thankfully. What I want to know is, what are the chances of using the Dominator to measure the speed of a tornado near the ground? Near the base of the tornado is one of the biggest mysteries of tornado science and it's also the most important to understand because it's those wind speeds that directly impact the structures and cause the destruction that we see with tornados every spring and summer. That's why we built this vehicle, it's to get up close and inside those and unravel those mysteries. So, if you could get this into a tornado, you can deploy something into it that will allow you physically to measure the rotational wind speeds? Yes. It is roughly what I was doing with bits of foam in the indoor artificial tornado. It's just with a real one. - Yeah! - It is, presumably, then, quite incredibly dangerous? Yeah, therethere is a level of risk involved, but, as a storm chaser, all I've done since I was 18 years old is get close to tornadoes. Which really begs just one question. Are you a scientist, an adrenaline junkie or a lunatic? - Probably all the above. - OK. Reed sounds like the perfect person for us. Using the Dominator, he can get really close to a tornado and he's already thought about how he could fire are here with this. What happens now? Well, we'll look to the southwest. If it's not moving side to side at all, it's likely coming right at us. So, I'll line up that left edge and make sure we're in the path. Then we'll drop the vehicle flush to the ground. I'll show you here really quick, and we're inside of course. - Yeah, that would be a good idea. OK. - Here it goes. - Is that supposed to happen? - Yeah. And then the spikes also go into the ground. And then there's the probe, right there and then a parachute will pop up when it's at peak flight, its 50 feet up and it gets sucked into the tornado. So, if everything works perfectly, that probe will have gone out of there and ended up in the tornado, spinning around and getting that critical rotational speed? Yeah, the tornado will pick it up. There's updrafts in the funnel as well, it will pick up the parachute, it will spiral around inside, measuring temperature, moisture and pressure at a rate of five times a second. - And all of that will happen? - It's going to one of these years. - OK. Good luck. - Thank you. - You never know. So, there we have it. The Dominator is going to take the place of our woman with a bucket. And its compressed air powered roof cannon does the job my catapult and paintball gun couldn't. Now all they need to do is find a real-life tornado and park next to it. Obviously that could take a very long time, so Reed and his team are on their own from now on, no film crew with them. Just them and the Dominator and a very ambitious mission. It actually takes six weeks but finally Reed and his crew are hot on the heels of a real-life twister. The trick now is to get as close as they dare. Close enough to fire a probe straight into its heart. But finding that heart turns out to be pretty tricky. That's our GPS position, that's the tornado, two miles southeast. We're getting real close! It's right here. A tornado can travel at about 70mph across the ground. Right here, guys. Stop right here. And change direction frequently and without warning. Which makes getting ahead of one incredibly difficult. Got to be up there. Right there! 'And they need to get to it quick. ' Turn around. Got to get it turned around! The life span of the average twister is just five to ten short minutes. Let's go! Let's go! There it is. On the right, see? Tornado on the ground, right there. Straight ahead, coming in, coming in, coming in. Straight ahead. Go! Whoa, that's huge! It is huge, about 100 metres across and at least a kilometre tall. Stop! Stop! Stop! Perfect! Fix it. Let's stop! Oh, my God! The tornado is coming straight for them. Get ready to shoot! It's perfect. Deploy! Deploy! Coming down! Not the best time for the Dominator's window to fail. Roll your window up, Reed. You have to roll your window up. - Here it is. - Tell me when. We're in it! We're in it! Shoot! Shoot the pole! - It's in. - It's right there, next to us! I've seen it go all the way round. It went one full revolution. It's in. They got the probe inside. I saw it make one full revolution then I lost visual on it, so I know it at least went around one time. But that's only half the challenge. Now they need to retrieve it to find out what it recorded. They wait for the storm to pass then set off, out through the trail of devastation in search of the probe. So how far ahead do you think it is? Probably about three miles, I would say. For some reason, they're not picking up its GPS signal so they're reduced to searching on foot. When I launched it I saw it go out over the road that way. It spun around like this, all the way around and it descended either behind these trees or these trees right here. We are within a couple of hundred feet of it right now. OK, so it's got to be somewhere over this way, over here. I had full visual Against all the odds, they spot it. THEY CHEER But the probe is damaged. It's trip around the twister has torn away the housing, leaving the electronics exposed. So, were they successful? The moment I get word, I'm straight on to Reed to find out. - Hi, Reed? - Hey, Richard! You got the thing into a tornado? - Yes, we did. - Was that a special moment? It was a very special moment, a very scary moment too, honestly, I think I might be getting a little too old for these tornado intercepts. But, our ears were popping from the pressure fall, it was a pretty intense tornado and seeing the probe take off was definitely an amazing feeling. - So, you've got it, you've got the probe. - Yep. The information is stored on it and what we want to know is the speed at the base and the different heights in the tornado. That data is possibly on the probe? I'm betting it's on the probe but we'll be able to get it off here. It should be any week, any day now. We've got so close! I mean, yeah, there it is. A lot of that. OK. Reed and his team have accomplished something that no-one has ever done before. They've managed to get a flying probe into the base of a tornado. CHEERING AND LAUGHING Today is the first time we've recovered one that we know was inside a tornado. This is a huge success for our science mission. I'd say this is definitely a stepping stone for things to come in the future. It's a proud moment. Unfortunately the probe turned out to be too badly damaged, so they're planning on doing it all over again. We've discovered what winds are and how they begin. How their paths can be used to predict the weather. We've seen the way a wind can start to spin. And how spinning winds are the basis for much of our extreme weather. More than anything, we are one step closer to revealing one of weather's greatest mysteries. How fast a tornado can spin. But, for the moment, the actual answer is still a weather secret. Next time, I try and capture a cloud, to see just how much one really weighs. This is a fairly unusual exercise, cloud collecting. I discover what would happen if rain fell in one big lump. I test the astounding hardness of hail. Oh! And the unbelievable speed of an avalanche. I'm speechless, genuinely speechless. You can find out more about Wild Weather with The Open University's free wall poster. Call 0845 030 3045 or go to . . and follow the links to The Open University.
Wild Weather Richard Hammond Download Torrent Full
Wild Weather Richard Hammond Download Torrent Download
12/20/14--18:51: _BBC - Wild Weather. Documentaries - AllCanDL.org All Warez Files Can free full. download Rapidshare Torrents Emules. BBC - Wild Weather with Richard Hammond 3of3 Temperature: the Driving Force (2014) HDTV. Richard Hammond investigates how wind actually starts. He visits one of the windiest places on the planet, walks into the centre of a man-made tornado and creates a 10-metre high whirlwind - made of fire!