字幕表 動画を再生する 英語字幕をプリント It's summer where Squeaks and I live, which means we've had a lot of thunderstorms lately! Summer thunderstorms usually have rain, thunder, and lightning, and sometimes strong, gusty winds. Sometimes the power even goes out! Good thing Squeaks and I keep a flashlight here just in case! But some areas of the world experience a really extreme kind of storm: a hurricane. Hurricanes are big, powerful storms that have strong winds. And I mean strong— In order to be considered a hurricane, a storm's winds have to be blowing faster than 119 kilometers an hour. That's faster than a car zooming down the highway! Sometimes you'll also hear this kind of storm called a cyclone or a typhoon, but they're just different names for the same thing. From outer space, many hurricanes look like this: big, swirling storms that have a really cool shape. [Squeaks squeaks] That's right, Squeaks, this hurricane looks kind of like a circle! The clouds wind around a space in the center of the hurricane, called the eye. It even sort of looks like an eyeball! Now, a hurricane's shape is pretty cool, but it's not the only thing that's special about this kind of storm. Everything has to be just right for a hurricane to form. It's kind of like a puzzle. All of the pieces have to be there, and have to fit together in exactly the right way, or a hurricane won't form. The first piece of the hurricane puzzle is warm ocean water. The water has to be at least 27 degrees Celsius, or about as warm as a swimming pool, for a hurricane to form. The warm water causes the air above it to warm up and rise high into the sky The warm air very humid, which means that there's a lot of water in it. This warm, moist air rises high into the sky from the warm water below. As the air rises into the sky, other air rushes in to take its place. The air that rushes in gets warm and humid, too, and then it rises high into the sky as well. As the air rises, it cools, and clouds start to form—lots of them! High in the sky is also where we find the second thing that's important for making a hurricane: wind. And not just any wind. The wind that helps make a hurricane has to be calm and steady. It can't be the kind of wind that blows really hard for a moment or two, then calms down again. If there are sudden gusts like that, the storm can get blown apart, like how a candle gets blown out. But if there's warm, damp air along with those steady winds, and it stays like that for a few days, the rest of the pieces that make up a hurricane fall into place. The steady winds push the growing storm over the ocean, and the warm water gives the storm energy. It causes more air to rise, more clouds to form, and the winds inside the hurricane to become stronger. In fact, the only place that it's not very windy is the hurricane's eye. It's actually very calm in the eye — even though it's right in the middle of the storm! As it grows, the hurricane also starts to turn. It spins around, with the eye in the center, kind of like a top. As long as hurricanes have that warm air for fuel, they can keep going … and keep growing! But when they reach land, or pass over cooler water, they lose their warm air, so they start to fall apart. Hurricanes usually leave behind a lot of rain, though. Sometimes the rain can last for days! They also can can push a lot of ocean water onto the shore, which can cause floods. But people can prepare for hurricanes, especially if they know when they're going to happen. For example, most hurricanes near North America happen between May and November every year, because that's when the different pieces that make a hurricane fit together the best. And scientists have lots of tools to try and track hurricanes — they use what they know about science to make really good guesses about where they'll pop up, where they'll go, how big they'll be, and how long they'll last. In places where hurricanes happen a lot, they usually build buildings in special ways so they won't get damaged by the strong winds or flooding water. And if you live or go on vacation in a place where hurricanes might happen, you can be prepared, too! You can talk to grownups about what you can do if a hurricane happens. That might mean like bringing in things from outside to protect them from strong winds, or it might mean helping to prepare a kit with food and water, flashlights, and a radio. b Speaking of flashlights, I know mine could use some new batteries. C'mon, Squeaks, let's go to the store. Thanks for joining us for this episode of SciShow Kids! If you want to watch more videos with me and Squeaks and you're watching this on YouTube, you can click the red subscribe button.