Radar capture from 5:25 p.m., Feb. 24, 2016 (Weather Underground)

The line of thunderstorms that rushed through the D.C. area Wednesday evening was arguably one of the fiercest since the June 2012 derecho.  The rare winter squall line slowed the evening commute to a crawl, unleashing flooding rain, damaging winds, and hail.

Severe thunderstorm warnings were issued area-wide between 5 and 7 p.m. and the storms were severe as advertised.


Summary of watches, warnings and damage reports from last night’s storms. (Jordan Tessler)

Wind gusts exceeded 60 mph bringing down trees. Some areas were pelted by marble-sized hail.

There was no escaping the monsoon-like rains, falling at rates of over an inch per hour – blowing in sideways sheets.

The squall line that ripped through the region was part of the same system that produced destructive and deadly tornadoes in southern Virginia.

The entire region was placed in a tornado watch Wednesday afternoon but the immediate D.C. area dodged a bullet as no actual warnings for tornadoes were issued north of Prince William County.

Tornado warnings were required in D.C.’s far southern areas. Funnel clouds were spotted in Stafford County and near Fredericksburg.

One reader in Dumfries photographed what appears to be a rotating wall cloud, from which tornadoes sometimes descend:

No tornadoes have been confirmed, but the National Weather Service is still investigating damage reports in southern Maryland and may conduct surveys, if necessary.

The wind

Wind damage, primarily in the form of downed trees, was scattered throughout the region. The damage tended to occur in pockets where microbursts – intense localized downdrafts from the thunderstorm complex – may have occurred. One such pocket occurred in Alexandria in the Del Ray neighborhood, from which we received several photos showing damage.

Peak gusts were likely in the range of 60-70 mph. A weather station in Germantown, Md. clocked gusts to 62 and 70 mph.

Photos

The hail

The hail that fell was generally between about 0.5 and 0.75 inches in diameter, the size of marbles. While this hail wasn’t large enough to cause real damage, the pounding proved frightening for commuters stuck in their cars.

Photos

The rain and flooding

The squall line unloaded torrential rain, frequently turned sideways by the roaring winds.

Rainfall totals, both from the squall line and earlier storms, were generally around an inch, but accumulated in a very short amount of time.


Doppler estimated rainfall totals, Feb. 24, 2016. (NWS)

Many streams and creeks overflowed their banks and streets turned into shallow rivers. Road closures and high water rescues were reported in a number of locations.

Photos

Lightning

The frequency of the lightning, energized by vast amounts of unstable air at high altitudes, might have easily confused the the thunderstorm outbreak with one occurring mid-summer. Readers captured some stunning cloud to ground photographs…

Photos

Was this event unusual?

Severe thunderstorms and tornadoes are certainly rare in the D.C. area during February, but not unprecedented. On February 21, 2014, a tornado watch was also issued for the D.C. area.

But this storm was more severe and widespread than the Feb. 2014 event.  In fact, considering its combination of intense rain, wind, and hail over such a large area, it was probably among the most severe squall lines to come through the region since the June 2012 derecho.

One could argue the intense complex of thunderstorms that tore through region in the middle of the night on July 1, 2015 was more intense over a concentrated area, but it did not cover the real estate of Wednesday’s event.