July 1, 2009

Climate change affects tornado activity

A U.S. study suggests the climate change effect of dry autumns and winters may lead to fewer tornadoes developing during the spring season.

University of Georgia researchers say global warming will likely mean more unpredictable weather conditions. They said their study indicates how drought conditions in an area's fall and winter may affect tornado activity the following spring.

The scientists said their study was specific to Georgia and the Southeastern United States, but further research could reveal patterns that might make the findings more general.

Our results suggest that there is a statistically significant reduction in tornado activity during a tornado season following drought the preceding fall and winter, said Associate Professor Marshall Shepherd, a meteorologist and lead author of the study. On the other hand, wet autumns and winters examined in the study had nearly twice as many spring tornado days as drought years did.

The researchers said they hope that one day meteorologists and climatologists might be able to predict the severity of a spring tornado season the way they now do for hurricanes.

The study that included Professor Thomas Mote, also of the University of Georgia, and Assistant Professor Dev Niyogi of Purdue University appears in the journal Environmental Research Letters.