2008 has been a big year in large part because the atmosphere has simply just brought the ingredients together more often than normal. Meteorologist Josh Wurman has been chasing twisters for fourteen years. He and colleague Sean Casey have been in the belly of the beast. Their adventures documented by the Discovery Channel. Wurman calls this volatile spring unusual, but not necessarily a sign of climate change.
This year has been active mostly just by chance. There have been a few outbreak days of tornadoes where there have been a lot of tornadoes, so the numbers are way up. The rest of the year may or may not be more active.
The higher numbers may also have to do with improved radar, increased awareness, and more eyes on the ground. Though 2008 is the deadliest year in a decade, it hardly compares to some of the deadliest ever which saw fatalities in the hundreds.
Still, the twisters have come early and often this year and show no sign of slowing.