How tornadoes form
Tornadoes can form in any situation that produces severe weather. They most commonly develop in thick cumulonimbus clouds-the same clouds that bring thunderstorms. Tornadoes are most likely occur when thunderstorms are likely-mostly in the spring and early summer, and often late in the afternoon when the ground is warm. The Great Plains usually have the weather patterns that can create tornadoes. The warm, humid air masses move north from the Gulf of Mexico into the lower Great Plains. The cold, dry air mass moves south from Canada. When these air masses meet, the cold air moves under the warm air, forcing the storms traveling from southwest to northeast. A single squall line can produce ton or more tornadoes.
Tornadoes occur more in the United States than any other country! In the U.S. about 800 tornadoes occur every year. The weather patterns on the Great Plains form what we call a "tornado alley". But tornadoes can and do occur in almost every part of the U.S.
The damage that comes from this monstrous storm is caused by both strong winds and flying debris. The low pressure inside the tornado sucks dust and other objects into the funnel. Tornadoes can move large objects such as sheds, trailers, cars and can scatter debris many miles away. One tornado tore off a motel sign in Broken Bow, Oklahoma, and dropped it 30 miles away in Arkansas! Some of the reasons the tornadoes are so frightening is that they are unpredictable. Some tornadoes can level houses on a street but leave neighboring houses standing. Tornadoes are ranked on the Fujita scale by the amount of damage each on causes. This scale was named for a brilliant scientist who actually devised it, Dr. T. Theodore Fujita. This scale goes from light damage (F0) to extreme damage (F5). We are fortunate that one percent of the tornadoes that occur are F4 and F5.
If a tornado hits your area what do you do? If a tornado is approaching a "tornado watch" will come on and warn you about the tornado. Make sure you watch for approaching thunderstorms. A "tornado warning" means a tornado has been spotted in the sky or an a weather radar. If you hear this announcement get to a safe place as fast as you can, and what ever you do don't wait until you can see it. One of the safest places to be during a tornado is in the basement of a strong well built building. If you are unfortunate and don't have a basement move to the middle of the ground floor and stay away windows and doors. Also make sure to avoid flying debris. When you are there find a sturdy piece of furniture to hide under, preferably a large table.If you are outdoors find a ditch to lie down in.