They always form over the warm waters of the tropical oceans (sea-surface temperatures must be above 26.5° C, or about 76° F) where they draw their energy.
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Try it risk-free Tornadoes are dangerous storms that affect millions of people. If you've ever lived in a place where tornadoes occur, this is a familiar sequence of events.
However, tornadoes can form in many different circumstances and places around the globe.
Hurricane landfalls are often accompanied by multiple tornadoes.
While their sporadic occurrence prevents them from drastically impacting the large-scale circulation, they still affect it in ways which must be accounted for and need to be better understood.
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In this video lesson, you will learn how and where they form, as well as how scientists classify tornadoes using the Enhanced Fujita Scale. Tornadoes are spinning funnel clouds produced by thunderstorm clouds.
Acting like an arm that reaches down from the thunderstorm cloud, these violent rotating funnels extend from sky to ground.
Tornadoes form from thunderstorm clouds, which form when warm, wet air rises very quickly.
As it rises, the cool air condenses into a large cumulus cloud.