Tuesday, 21 May, 2013

Classroom Activity Page: Tornadoes are capable of serious destruction. What gets them twisting? Where do they get their energy? How can we protect ourselves when a tornado is approaching?

Tornadoes need wet air, dry air, and wind shear. What explains the big improvement in tornado prediction? Is climate change boosting these storms?

What is a landspout tornado? “Landspout” is slang for a tornado that, unlike most tornadoes, is not associated with the mesocyclone of a thunderstorm. The name reflects the fact that these tornadoes look “like a weak Florida Keys waterspout over land.” Landspout tornado over Hale County in Texas (NOAA). The official name, “dust-tube tornado,” comes [...]

How does tornado season vary across the United States? Tornado season begins as early as late February or early March in northern Texas and Oklahoma, the southern portion of Tornado Alley, where the tornado threat remains through most of May. By early June, the greatest threats tend to lie to the north, in Kansas and [...]

A tornado that’s 500 meters in diameter looks a lot more ominous than the average twister, which is “only” 150 meters across. All other things being equal, larger tornadoes are more damaging, but size is not related to wind speed. Instead, wind speed increases along with the difference between atmospheric pressure inside the funnel, and [...]

Tornadoes can happen whenever atmospheric conditions are suitable, says Steve Ackerman, professor of atmospheric science at UW-Madison. Over the years, Wisconsin has had at least one tornado in every month except February. “To get any severe weather, we need really warm, moist air near the ground, and cool air aloft, which is typical of the [...]

Scott Bachmeier, a research meteorologist at the Cooperative Institute for Meteorological Satellite Studies at UW-Madison, says that particles in the air scatter light. In the day, the particles scatter more violet and blue light, but our eyes are more sensitive to blue light — that’s why the sky appears blue. Thunderstorms, which can be the [...]

Tornadoes kill 60 Americans each year. How do we predict tornadoes? How do we make houses safer? Where do tornadoes get their energy?