Climate Central has developed a map which shows where the greatest concentration of tornadoes have occurred in the region by county.
Charles County, Md. averages the largest number of tornadoes per year in our region, and a hypothesis is that local interactions between cool breezes from the Chesapeake Bay and larger scale hot air masses over the region have enhanced the activity there.
Why aren’t the tornadoes as strong and frequent in our region compared to the Midwest? The Appalachian mountains provide a bit of a barrier, preventing the inflow of some of the warm, unstable air that fuels storms in Tornado Alley (of the Plains) and the so-called Dixie Alley (of the South).
BuzzFeed has a great pictorial explainer which shows how the convergence of dry air to the southwest, cold air from the northwest, and hot, humid air from the southeast converge in the vicinity of Oklahoma and the Plains, making it the most vulnerable location in the world for tornado formation.
CWG’s Kathryn Prociv will have a more detailed post on D.C. area tornado climatology tomorrow.