4 April 2011
A line of heavy and severe storms crossed North Alabama and Middle Tennessee today, with numerous reports of trees and power lines down. During live coverage of the storms, I spotted a dust foot on our live camera on top of the Saturn 5 mock-up in Huntsville. A dust foot is an indicator that a microburst has occurred and that strong winds are very likely.
A microburst happens in severe thunderstorms when rain cooled air (high in the storm) falls toward the ground and spreads out rapidly. It may not seem like it, but a blob of cold air can fall just as fast any other object, and winds of over 70 mph are common in these events. They are many times mistaken for a tornado and can do similar damage.
A big thank you to Ted Zingarelli for grabbing a picture of the dust foot and sending it to me. If you ever see one of these, watch out for strong winds. Road signs and power lines were knocked down by this microburst. Wind gauges recorded a gust to 68 mph nearby.