 Hi there, my name is Jeff Weber and I'm an Arctic climatologist at the Unidata Program Center in Boulder, Colorado at UCAR NCAR. This is Max Weber. He's my assistant. He's a wizard in training and he'll be doing some of the work with us today. So what we're going to be doing is we're going to be representing extreme cloud formation. Now, as you saw in the last module, hot air rises, and as that hot air rises into the atmosphere, it makes a cloud. And what we're going to do here is we're going to amplify that effect by using dry ice. Now we call it dry ice because if you were to take this ice and set it outside like this after it melts, there would be nothing left. We call that sublimation. It goes from a solid to a gas. Some like water ice, which is frozen water, this is frozen carbon dioxide. And so carbon dioxide is present in our atmosphere and it's a lot colder when we chill this one down. Frozen carbon dioxide is minus 110 degrees Fahrenheit, whereas, you know, water ice is 32 degrees Fahrenheit. And so normally what happens here on the Great Plains in Tornado Alley, you'll have the very warm, moist air from the Gulf of Mexico coming up into the High Plains. And that interacts with the cold air from the Rocky Mountains. Now warm and cold air don't like each other very much, as you might assume with Mike Nelson's tornado dance. And so that creates instability. And the difference between the warm and the cold, the greater that difference is, the more unstable the atmosphere becomes. And so generally speaking, when we have tornadoes, we're talking about 90, 95-degree temperature coming out of the Gulf of Mexico, interacting with maybe minus 40-degree temperatures from the atmosphere loss coming out of the Colorado Rocky Mountains. What we've done here today is we've got a cauldron of boiling water at 212 degrees and a dry ice, which is minus 110 Fahrenheit. So it's about 300 degrees difference in temperature between the dry ice and the boiling water, whereas here in our environment in the United States, with a 90-degree Gulf of Mexico air and minus 40 with the temperature of the air aloft, it's about 130 degrees difference. So we should see a much more dramatic effect here for these cloud formations as we pour this dry ice into the pot of boiling water. Now you have to be careful with this because dry ice is very cold. If you're not wearing gloves, it could freeze or burn your hands. So please, you can do some of these activities at home. You can do dry ice activities at home, and you can actually buy dry ice at many of your local grocers. People use it when they go on camping because it's dry ice. So when you put the dry ice in your cooler, it doesn't melt and make all of your food wet and soggy. So it's a very popular item for campers to use in their coolers. Now I know there's a lot of family and friends out there watching today. I'd like to say a big hello to Crosby and Lorelai and Emily and Phil out there in Denver and all the other friends and family. Now we've had some small clouds forming here. We've got some dry ice and some warm water, and it's kind of puffing up some what we call like small little clouds. These are the things that you might see on a day-to-day basis, kind of like here in Boulder, Colorado that we're having today. We've got some nice dry ice going here, making some other small clouds as well. But as wizards, we kind of like to make things go big. And so what I think we're going to do now with my assistant is we're going to take this dry ice, there are very large bowls of dry ice, and another large bowl of dry ice, and we're going to pour that into this cauldron of boiling water, and it's going to create an incredible cloud. Now this is exactly the type of situation you would see in a very active thunderstorm that's going to create tornadoes. You'll get this incredible vertical motion up and down inside the thunderstorm. And that's what creates these supercells, that's what creates these tornadoes is this incredible vertical motion interacting with a jet stream aloft. And so if you see some sort of tornadic activity here as this begins, I wouldn't be surprised because oftentimes that's what we get. So fasten your seatbelts, and we're going to have some extreme cloud formation with my help from my assistant Max. All right, now we're wearing gloves, we've got our eye goggles, protective covers on, we've got our widget hats, let's make an extreme cloud. All right, everybody, let's count it down. Three, two, one. So this is extreme cloud formation. This is like the cloud tops you would see on top of a supercell thunderstorm. Notice how the clouds are rising up and bubbling and churning. This is exactly what happens inside a big thunderstorm when you're out and about on the high plains. And this roaring air as the wind comes in, this is kind of how tornadoes get started. You get this vertical velocity, they bend it and they twist it and they get the tornadoes going. So that's our extreme cloud formation. We have to take any questions about anything weather or anything about clouds. That is so cool. Is this something that people could or would be able to try at home? Well, yes, Tiffany, dry ice is very cold. It's a minus 110 degrees Fahrenheit. So you have to wear gloves when you're handling it. And the boiling water is also very hot. But if you take proper precautions, have gloves, eye protection, cover your whole skin so you don't get freeze or burn or blast from the boiling water, then you can take care of these things at home. And as I mentioned earlier, you can get dry ice at many of your local grocers. Awesome. We don't have any questions coming in quite yet from the audience, but I have one because you know, I always have questions. Tell me about, we're talking about these extreme storms like tornadoes and thunderstorms and I'm betting that pretty much everybody is familiar with hearing at times of a tornado or a severe storm watch or a warning. How do we know the difference between a watch and a warning? Yeah, that's a really good question. Now, we have a tornado watch that indicates that's where we're our protection for that big blow up right there. We have a tornado watch that means the conditions are right for tornadoes. And when I say conditions are right for tornadoes, those are the elements that we just discussed today, having that very warm moisture at the surface and very cold air locked creating that instability. And just the elements that we know need to be included the ingredients that we need for tornado. So that's what we put out a tornado watch a tornado warning is when we know we have a tornado actively on the ground. And so when you have a tornado warning, definitely type of soup shelter that means we have an active tornado in your area, whereas a tornado watch just needs the atmospheric conditions are ready for tornado development. Okay, that's good for everybody to know, I think. And there was another question, actually, if anybody was on the last one there was a question about ice cloud formation, and Tim actually said that potentially you could expand on that. Sure, I'll expand ice cloud formation and also about cloud formation in general. First off, all cloud types, except for one need vertical motion to make the cloud, you have to rise that warm oyster up to where it becomes liquid water, we call it the lifted ice cloud formation level because the vapor is turning into water, creating the clouds. And so all clouds need that vertical motion to create the cloud types. However, there's one type of cloud that forms in descending air. And those are the mattress clouds, and that's when the cold air a lot is no longer being held up there by the vertical motion of the thunderstorm that colder starts to fall down. When the cold air falling down interacts with the warmer, it creates these mattress clouds. They kind of look like falling pillows. It's an incredible sky. We see them here in Colorado very often after thunderstorms. They're indicative of the fact that the thunderstorm has come to a close. Now as we go into ice clouds, as I was saying we lift the water vapor up to where it condenses. We lift that water up and it condenses and becomes water. If we lift it up there and it's so cold that it becomes ice crystals, then we have an ice cloud. Now sometimes the air is so cold at the surface that we either have ice crystals or an ice fog here on the surface. So what's really important about whether you're going to have a rain cloud or an ice cloud is the temperature of that environment. And if the temperature of that environment is below freezing, the water will form as ice. You'll have an ice cloud, and those need to be aloft up in the sky. We can even have ice fog, which is down here on the ground. And that's one of our favorite types of days here in Colorado is when we have ice fogs. It's a fantastic experience to be walking around an ice fog. I really love it. Yeah, that just sounds cool. We have, I'm going to actually combine a couple of questions here for you Jeff, because Leif is wondering generally a little bit more about the experiment that you just showed us what are clouds made of, and how does dry ice and hot water form clouds. And then you might even follow with Lydia, who's four years old and joining us today is wondering how the clouds turn into rain. Hi Lydia, and thank you all for the questions. Well, how do clouds form rain. This is, this is a really fun question. Clouds are made up of water. And they're just floating up there and they're keeping the water up in the sky because there's that rising warm air. Now once those water droplets get big enough that that rising warm air can't keep them up in the air anymore. They just fall from the sky. And that's how we get our rain. And so it's really a matter of the rain drops getting big enough that they can fall from the sky, but they're no longer being held up by the rising warm air. And so that's how we get a rain. And I'm sorry, Tiffany what was the other question. Yeah, sorry I gave you too many at once but but the other piece of all that was how does the actual the dry ice and the hot water what's that doing to form clouds. We're getting kind of a double cloud we'll use the dry ice and the hot water, because when we put the really cold dry ice into the water. It's making the the the boiling water condensate around the cold dry ice, but some of that dry ice is releasing carbon dioxide which is what it's made of as a gas as well. So we pour the dry ice into the hot water we're getting water vapor clouds, as well as carbon dioxide clouds. Now that's why we did it outside, because carbon dioxide, although it's in our atmosphere all the time, it is somewhat poisonous to humans, we exhale carbon dioxide when we breathe in oxygen, we breathe out carbon dioxide so our bodies are getting rid of carbon dioxide. So carbon dioxide is also a greenhouse gas, and it's formed when you run fossil fuels like either coal plants or cars, we've enforced fires release carbon dioxide to the atmosphere, and that carbon dioxide absorbs the radiation from the earth and the sun and we radiate it's back to the earth, and that's what we call it a greenhouse gas. So, while carbon dioxide is very helpful for plants, it's not very beneficial to humans. And so plants, I'm like us they breathe in carbon dioxide and breathe out oxygen, whereas we breathe in oxygen and read out carbon dioxide so we have this really nice relationship with the plant world here on this planet, where we have this symbiotic relationship we use what they don't and they use what we don't so that's really kind of neat. So, what we're doing is carbon dioxide with the boiling water, we're getting two types of clouds we're getting the water cloud and a dry ice cloud a co2 cloud. Okay, that's great to know and in fact, you kind of just brought up one of the other questions which was is is carbon dioxide is co2 safe when it's in our air that we're breathing. Yeah, and it is safe because it comes out of our bodies all the time every time we exhale we're breathing out carbon dioxide, but there's a reason we're breathing it out it's because our bodies can't use it we're using the oxygen. And so yes it's relatively safe, but if you're in a room completely filled with carbon dioxide, there'd be no oxygen and you wouldn't be able to breathe. And so that's when it becomes unsafe. It's also unsafe when we get the levels so high in our atmosphere that our planet warms. And that's kind of where we're at right now we're increasing the carbon dioxide and our planetary system, and that's warming the planet. And so, while it is safe, and it's beneficial to plants, it does have a side effect of warming the planet, obviously the human body does not like carbon dioxide that's why we exhale we get rid of it as we breathe. Okay, that makes sense great. Thank you. This is a cool question from Evan and I bet a lot of people might be wondering this, can I make my own mini tornado. Hey Evan. Yes, we all like to make mini tornadoes. If you've ever been up to the NCAR Mesa lab, we have a display where they create a tornado. Now, what would be a fun way to do that there'd be a couple of ways to do that, but you're gonna have to have some sort of forcing some sort of fans. You get one fan right underneath an experiment like this to get the rotation, or you get like three or four fans and place them at angles around and get the spinning that way. So you're going to have to have some sort of mechanical force some sort of forcing to get that spin going. Whereas, here on earth what we have to get that that energy is the jet stream aloft, and all the winds combining at the surface to give us all that energy and since on a smaller scale we have to create the energy generally with fans or or something along those lines and so that's the way to create your own tornado is to create these clouds like this and then get them spinning with some sort of fan action and you can get some really cool stuff and up at the Mesa lab when we do open back up, you can come and visit our displays there and see our inside tornado. Absolutely I hope that's going to be sooner than later. I love those lines I'm skipping around through some of the questions because they're kind of leading into other ones. And max is asking how does a tornado get its spin, which is you were talking about how we could do it. Sure. Well max that's, I love your name. This is my max so good to see you back up there on the internet. Max's are everywhere it's raining max is here's the thing we're still studying tornadoes in their formation and we're not exactly sure how they form because some thunderstorms look exactly the same as ever thunderstorms and get one will produce a tornado and another one won't. So there's a couple of ways that tornadoes are thought to to form the prevailing thought is that as wind speed changes with height, we call that wind shear. Generally speaking, the wind is higher as you get up in the atmosphere that it is along the surface, primarily because of houses and trees, causing friction at the surface. So as you get a little bit higher above all the boundary layer obstacles, the wind can be faster. And so, since the wind increases with speed as you go up, it kind of creates rotors rolling wind. Now this one is horizontal. That's not quite a tornado yet but you get these these horizontal rollers at the beginning of the thunderstorms because of this increasing wind speed with height. And then when you hear people talk about tornadoes tornado forecast will talk about upper level support or upper air support. And what you need is to have the jet stream. Ideally, come right over that thunderstorm that the jet stream, which is the high winds of about 25 to 30,000 feet in the atmosphere. When you're zipping over that thunderstorm, it creates a low pressure. It's kind of like when you're in a shower with a shower curtain, and the shower curtain tries to draw in towards the shower. That's because the stream of water is creating a lower pressure inside the shower than it is outside that draws the shower curtain in. Think of that in the reverse and having the jet stream aloft going by really high. And here's the spinning rotor underneath it. It gets stretched upward that horizontal roller gets stretched until it gets to be vertical. And that's how we create tornadoes. That's at least a prevailing current thought. There's still a lot to be learned about tornadoes and then it's one of the areas of research at the National Center for Atmospheric Research because we still don't know exactly how and why they form. Really great question. Thanks for asking that one. Maybe some of you who are watching today might end up being scientists studying tornadoes and learning more about them over time. So thanks, Jeff. We have time for just a couple more questions. I just did want to say, Joe, and a lot of people agreed just that that is a cool cloud in the cauldron, and I agree too. They're enjoying that. It's a lot of fun. It's a lot of fun. So we'll try to get to a couple of more questions. Wallace is asking, what's your favorite type of cloud? My favorite type of cloud is the lenticular cloud, also called a lens cloud. And we get those a lot here on the front range of the Rockies. And the reason I like the lenticular clouds the most is they're the only clouds that actually have air go through them, and they stay in the same place. It's a standing wave in the water. And so the cloud stays the exact same location all day, and the air is going through it. So the cloud is constantly changing what it's made out of, but it's staying in the same place. And they make for incredibly beautiful sunsets. So lenticular clouds I think are probably my favorite. Great question. There's so many clouds. I love clouds. I love to stay and look at all the clouds in the sky and name them and figure out how they formed. It's a fascinating study. Okay, here's another good question. What's the temperature of a cloud? These are great questions we're getting today. Wow, yeah. And so the temperatures of clouds can change dramatically. For example, you can have noctilucent clouds, which are really high clouds over the Arctic, like 50 miles off the surface. And they're really cold. They're like minus 40 degrees Fahrenheit. Most of the clouds that we see when the vapor comes up and condenses, usually the cloud bottom height is right around 32 degrees, because that's where our water vapor will be condensing into a liquid. And so, depending upon the base of the cloud, they can change in temperatures. The lower base clouds are going to be warmer, and the higher base clouds are going to be colder. And so, when they get below 32 degrees, they're forming the ice clouds. And so there's a lot of different temperatures and clouds. For example, temperatures of clouds and hurricanes will be very, very mild, you know, 70, 80 degrees. Clouds here in Colorado today, the bottom of the clouds might be 40, 50 degrees and the top of the clouds might be 10 or 50 degrees colder than that. So, there's a lot of variability on the temperatures of clouds based primarily on how high in the atmosphere they are, what type of season it is, and where on the planet they're located. Great. Okay. Thank you. These are, we've definitely have some weather fans joining us this afternoon asking some great questions and we may not have time to get to them all but we're going to cruise through a couple of more. Karen's wondering how quickly do severe weather clouds form. That's a really good question and severe weather clouds can form very quickly. If you have the right ingredients such as a very warm moist air mass interacting with a very cold air mass, things can get severe in a matter of 15 minutes. They can spin up very quickly. If you watch thunderstorms in slow motion or on time lapse, you can see they start off very slow. Let me get this rapid blow up to the top and that explosive blowing up from like a 20,000 foot top to like a 45,000 foot top can take place in five or 10 minutes. And so, things can change very quickly in the atmosphere, especially if you have the right ingredients, which is really warm moist air and very cold drier that increases the instability and really gets that vertical motion going. So, things can get severe very quickly. I've seen radar scans where on one radar scan there's nothing there, then five minutes later another radar scan comes by and it's already gone severe. So, things can happen very quickly. Wow. That's incredible. Okay, let's jump into one more because this is another good question. Why are some clouds more gray and others are so bright white? Yeah. Yeah. It's a great question because when you look at the clouds, if they look very white and very shiny and bright, there's probably not a whole lot of water in there. Now, as they build more or larger water droplets, they block more and more of the sun. So, they look darker and darker. And so, when you look at the cloud base and it doesn't look very dark, you probably are not going to be expecting much rain. But if you look at the cloud base and it's very dark, that means it's absorbing all the sunlight and that means there's a lot of water in there and it's about to rain really hard. And if you look at the base of the cloud and you can kind of see a greenish hue or tint to it, that's the ice absorbing the sunlight and giving a little bit of the green light back out. And that's what you can tell if there's going to be ice or hail in the storm. And so, just being on the ground, you don't have to have a radar or a satellite or a sophisticated model to tell you what the weather is. You can tell a lot of the weather just by looking at the clouds. And if you look at a white puffy cloud, say, well, it's a fair weather cloud, probably no rain. If you look at a humans cloud, it's got a very dark base. It's probably still a lot more water, bigger raindrops, and it will probably rain soon. Yeah, I actually grew up in Texas and when we had tornado weather and the possibility of tornadoes, we used to say that the sky looked green. That was really weird. When the sky is green, if you're ready for some severe weather, there's no doubt about that. Okay, we only have time for one more question but since I just brought up tornadoes again. Griffin is wondering how big can tornadoes get. That's a fun question. Probably the largest tornado in the United States was the El Reno tornado, which is about four years ago. It was three miles wide. So, that's dramatically why that's incredibly like most tornadoes are not on that scale, but they can get multiple miles in the width and so you're talking about an area. 30 blocks wide with tornado force winds and so they can get to be fairly large. The El Reno tornado is a really big tornado, most of them are like a quarter of a mile wide, you know, 1000 feet or 1500 feet wide but the El Reno tornado in Texas, Oklahoma was three miles wide. Wow. That's incredible. Well, it's been so fun exploring some of this extreme weather and these extreme clouds with you and if, if people have been in the presentations before if they might have already seen I just wanted to make sure that you know that I'm listening to my cumulus cloud earrings today in honor of all of this talk about weather and learning about weather. Yay, cumulus clouds. We want to thank everybody for tuning in today. My assistant Max wants to thank everybody for tuning in and science is fun. We love Super Science Saturday. We're looking forward to seeing you all in person hopefully next year. I'll put the NCAR Mason lab as we do this again next year. Thank you so much Jeff and Max and if anybody is going to join us again we're going to make a very quick transition and we have another show starting at 130 or perhaps 132. Thanks so much. Bye.