Another statistic that intrigues Dr. Isaacs and his colleagues is that a third of northern tornadoes spun clockwise before the rise of highway usage. Today, these wrong way tornadoes are rare, a phenomenon he believes may be due to right-side driving. In the Southern Hemisphere, most tornadoes move clockwise, suggesting to Dr. Isaacs that our neighbors to the south would be wise to drive on the right. Most experts do not agree with Dr. Isaacs and his fellow authors, Dr. Gerald Wicks, James Stork and David Goldstein. Dr. Allan Pearson of the National Severe Storms Forecast Center in Kansas City thinks increased irrigation in the area of tornado activity may be one reason for the increase in more tornadoes.
Irrigation increases humidity, a factor in tornado formation.
An alternative explanation, he adds, is the new popularity of X-rated movies. This site is designed for use with a 3.0 or later version browser.