Transcript:

Heres a program from our archives.Tornados - Stormy Weatherambience: ThunderstormAbout 1,000 tornadoes occur in the United States every year - more than in any other part of the world. But the season to watch out for tornadoes varies, depending on what part of the country you're in. I'm Jim Metzner, and this is the Pulse of the Planet.Alfred Bedard is an Adjunct Professor at the University of Colorado.Bedard: Tornadoes tend to occur in the southern states in the early part of the year, even in the mid-winter months. Georgia, Alabama, Mississippi, Florida - they tend to have the most frequent tornadoes in the January to March time frame and then as the summer starts to approach, the frequency of tornadoes increases in the upper United States.Basically the tornadoes feed off of the very, very strong energy that is inherent with severe weather. Whenever you have very severe weather, that's when tornadoes tend to appear. So the pattern of severe weather occurs in the southern states in the early part of the year, even in the winter, and then, as the summer approaches, the strong severe weather moves to the north, and the tornado frequency follows that, because the very severe weather also produces the conditions that lead to tornadoes."Pulse of the Planet is presented by the National Science Foundation. I'm Jim Metzner.