Thursday, December 18, 2008

"Tornado Rampage" on the Discovery Channel

On December 18, 2008 The Discovery Channel presented “Tornado Rampage”, a cornucopia of live storm-chaser footage of twisters, mostly in the Midwest, as far back as 1991.

The program started with winter tornadoes, the outbreak in the south on Super Tuesday, Feb. 5, 2008, with interviews of students at Union College in Tennessee.

The program showed chilling footage of the May 2008 tornadoes that destroyed Pitcher, IA and that killed several boy scouts camped in a river valley area that should be been less exposed.

Another impressive sequence took place in Windsor, CO with a hailstorm first.

The show explained that a supercell is a large persistent rotating thunderstorm. The rotation occurs because of squeezing in the atmosphere as warm moist air from the southeast collides with cool dry air from the northwest. The twister is an example of the principle of the law of the conservation of angular momentum (a good question for a physics quiz).

The show presented some large wedge tornadoes, which often blacken part of the sky to the ground. Smaller tornadoes often seem to appear near the ends of storms in areas where rain has already past.

The show maintains that it is not a good idea to wait out a tornado under a highway underpass. The structure could increase the windspeed with a Bernoulli effect. It is safer to lie face down in a low ditch.

Other major tornadoes shown included Greensburg, KS in 2007 and a 1999 of 66 tornadoes near Oklahoma City. Sometimes there are multiple twisters and supercells forming north to south over an area.

I recall the tornado outburst on March 30, 1998 in Minnesota. I was in northern MN and returning to Minneapolis with a friend when we got caught in a violent hailstorm, unusual that far north that early in the Spring.

Update: June 21, 2010

MSNBC has a fascinating video of one tornado circling another in South Dakota

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