Research suggests urban sprawl, wet falls and winter affect severe weather
Previously rare big city storms -- like a tornado August 19 that downed trees and ripped off roofs in downtown Minneapolis and the powerful thunderstorms in New York City a day earlier -- may not be so unusual anymore.
As large urban areas continue to expand, they appear to influence tornadoes and other severe weather, research suggests. Cities could be even more at risk if located in a region experiencing a wet fall or winter, according to researchers from Purdue University and the University of Georgia.
Read more at http://news.uns.purdue.edu/x/2009b/090908NiyogiWeather.html