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Weather facts
Tornado reports almost double so far this year
Related: Our guide to tornado safety
Photos: 1974 Xenia tornado | 2000 Xenia tornado | More tornado photos
Tuesday, May 06, 2008
Reports of tornadoes and tornado damage has been common on local and national newscasts this year.
The 2008 tornado count is up considerably, from past years. Through May 5, 731 tornadoes have been tallied nationally.
Extras
At the end of April 2007, there were 409 tornadoes; in 2006, 454; and 2005, 237.
So far this year, no tornadoes have been reported in the Miami Valley, although funnel clouds were spotted in Clark and Champaign Counties on Feb. 17.
Many tornadoes this year have been in the Deep South as well as along a corridor from west Texas through Oklahoma, Kansas, and Missouri and into western Illinois.
This is not unusual, as this is the heart of Tornado Alley. However, to have as many as we have seen in that area this early in the year is a bit rare. The Tornado Alley season typically comes from April through June. Still, to have many tornadoes there in February and March is unusual.
So what's going on? Tornadoes feed off of a few ingredients. One is a very strong jet stream, which can add energy to the thunderstorms that spawn tornadoes. Another is a strong low-level flow of warm humid air from the Gulf of Mexico that helps the strong updrafts form in storm which can be very helpful in tornado formation. The third ingredient is a strong contrast in air masses, between the warm, humid air to the south and cold air to the north, causing storms to strengthen.
Also contributing is spring snow. Less than two weeks ago nearly two feet of snow fell in Minnesota and the eastern Dakotas. With snow on the ground, very cold air was able to travel farther south than we typically see this time of year. Also with snow on the ground in the Upper Midwest late in the spring, the storm track was positioned to point the jet stream between the cold air sitting over the snow and the warm air that naturally occurs this time of year over the southern Mississippi Valley. This set up has repeated itself a few times in the last few months and the result has been the perfect pattern for not only a large number of tornadoes, but powerful and deadly ones as well.
