In Glogpedia

by MrReGlog
Last updated 8 years ago

Earth Sciences

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How do tornadoes form? Most tornadoes form from thunderstorms. You need warm, moist air from the Gulf of Mexico and cool, dry air from Canada. When these two air masses meet, they create instability in the atmosphere. A change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. Rising air within the updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.

What is a tornado? A tornado is a violent rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of up to 300 mph. They can destroy large buildings, uproot trees and hurl vehicles hundreds of yards. They can also drive straw into trees. Damage paths can be in excess of one mile wide to 50 miles long. In an average year, 1000 tornadoes are reported nationwide.

What Kind of Destruction Do Tornadoes Cause? The Fujita scale classifies tornadoes according to the damage they cause. Almost half of all tornadoes fall into the F1 or "moderate damage" category. These tornadoes reach speeds of 73-112 m.p.h. camper vans, rip off the roofs of houses, and uproot trees. Only about 1 percent of tornadoes are classified as F5, causing "incredible damage." With wind speeds in excess of 261 m.p.h., these tornadoes are capable of lifting houses off their foundations and hurling them considerable distances.


Where Do Tornadoes Occur? The conditions that lead to tornadoes happen mostly in the central and southern U.S., where warm, humid air from the Gulf of Mexico collides with cool, dry air from the Rockies and Canada. This area, is called "tornado alley," and it extends roughly from the Rocky Mountains to the Appalachians, and from Iowa and Nebraska to the Gulf of Mexico. Tornadoes can also happen elsewhere, though, including all U.S. states, Europe, Asia, and Australia.



  • hartbarbara 8 years ago

    hartbarbara's avatar

    Cool pictures C: I can acually see the objects flying in one picture.