Fortunately, the Washington, D.C. area does not experience tornadoes that are as frequent and intense as the Plains and Southeast. However, weaker tornadoes are not uncommon.
This map below, created by CWG’s Kathryn Prociv, does a nice job of illustrating the region’s tornado history, showing the paths and intensity of the various twisters between 1950 and 2011, totaling around 460 (or 115 for the District and the surrounding counties listed in the Climate Central map below).
As you can see, the majority of twisters to affect the region have been of the weaker F0 to F1 variety on the 0-5 Fujita scale (which has now been replaced by the EF, Enhanced Fujita scale). But the tornado that touched down in La Plata, Md. in 2002 was an F4.
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.