WASHINGTON — Trees bending to the will of the wind, power lines snapping, and streets looking more like rivers-- that was the chaotic scene over the D.C. Metro area Thursday evening, just before a tornado warning was, rather unexpectedly, issued for the region.
While tornado warnings impacting the region surrounding D.C. occur more frequently, this was only the sixth time in 17 years that a warning including the District proper was issued, according to records kept by Iowa State University.
A Rarity In The City
Tornadoes in D.C. are rare. Between 1950 and 2017, there have only been six tornadoes to hit the District's boundaries, with most of them producing minor damage. Tornado data from the Storm Prediction Center shows that in 2001, an F3 tornado-- which can produce winds between 136 and 165 mph -- moved through D.C.
From 2005 - 2021, 436 tornado warnings were issued across the DMV, but only six included the District itself.
What Happened To Create These Conditions?
Earlier in the day Thursday, a tornado warning covering parts of Prince George's and Anne Arundel counties was issued, as part of the first wave of severe storms began passing through the DMV. Numerous wind damage reports came out, as downed trees and utility lines caused power outages for thousands of homes in the area.
Based on the amount of moisture in the atmosphere, the CAPE (convective available potential energy) and wind shear (a change of wind speed or direction with height), forecasters knew the wind would be the main threat, along with the risk for flash flooding.
Shear profiles became more favorable for severe weather as the second wave of storms hit later in the evening. Wind shear helps storms to become stronger and last longer, and aids in storms rotating, increasing the chances of tornadic activity.
As the cold front got closer, the air was still unstable, especially along a boundary of cooler air versus warmer air. The atmosphere doesn't respond well to boundaries, making it a focal point for showers and storms.
Shortly after 9 p.m. in D.C. blinding rain fell and the rare weather warning was issued: A tornado warning. The National Weather Service is still working to confirm if an actual tornado occurred in D.C. or the surrounding areas. More than 120 storm damage reports were submitted to the National Weather Service following Thursday's storms.
Tornado Safety Tips
- Prepare an emergency kit: Recommended items include water, non-perishable food, medication, fresh batteries and a battery-powered/internet-enabled device to listen to weather updates.
- When a tornado warning is issued, or if you see signs of tornadic activity, take cover immediately in the basement or an inside room without windows on the lowest floor.
- Get under something sturdy(a heavy table or workbench) and cover your body with a blanket, sleeping bag or mattress.
- Protect your head with anything available.
- Avoid sheltering in rooms with windows and do not stay in mobile homes.