Crews clearing downed tree limbs and debris at the John Paul Jones Memorial in West Potomac Park in Washington. (National Park Service)

An intense thunderstorm squall line raced into the Washington region late Thursday afternoon, unleashing widespread damaging winds that took down dozens of trees and power lines around the region.

One tornado was confirmed near Columbia, Md. The National Weather Service investigated the possibility that another touched down in the Mall and Tidal Basin area, where tree limbs and branches littered the ground. But, after surveying the damage, they said evidence was “inconclusive” of an actual tornado, according to James Lee, meteorologist-in-charge of the Weather Service office serving the Washington region. Lee said in an email they are estimating straight-line winds of 70 to 80 mph raked the area.

The Weather Service had issued a tornado warning for the District at 3:47 p.m. Thursday, which was discontinued 11 minutes later when the storm exited the District and its rotation weakened.

After the storm, the National Park Service described “widespread tree damage from the Lincoln Memorial to the Washington Monument and around the Tidal Basin and Hains Point.”

Lee said the Weather Service received more than 20 additional reports of tree damage extending into Southeast Washington, near Massachusetts Avenue.

Weather radar provided subtle indications of rotation as the responsible storm tracked from roughly Rosslyn through the southern half of the District, but no photo or video emerged of a tornado actually on the ground.

Over the course of Thursday afternoon, the Weather Service issued 19 severe thunderstorm warnings and two tornado warnings, which collectively covered almost the entire region. In the storms’ aftermath, it filed over 75 reports of wind damage, mainly to trees.


Severe thunderstorm and tornado warnings issued Thursday and reports of damage obtained from National Weather Service. (Jordan Tessler)

Rather than tornadoes, much of the damage in the region was incited by downburst winds. These winds, which radar estimated reached 70 to 80 mph in a few areas, originate from the cloud and punch down to the ground before fanning outward in all directions. Their gusts can be extremely powerful, on par with weak tornadoes.

The strongest downburst in the region slammed Falls Church and Arlington County (including parts of adjacent Annandale and Alexandria) where radar estimated gusts in the vicinity of 80 mph. Reagan National Airport clocked a 68 mph gust.


Doppler image of downburst/weak mesocyclone over Arlington and Washington, D.C. Arrows are author's interpretation of airflow. (Jeff Halverson from RadarScope)

In this part of Northern Virginia, we received dozens of reports of downed trees and power lines as well as dramatic video of exploding transformers:

Dave Statter of Falls Church, in email, wrote that he had just arrived home when “all hell broke loose.” A large tree split in his yard, falling over his fence, breaking one rail. Another trunk of a multi-trunk tree fell on his driveway.

Jane Chicaharito of Falls Church could not enter her home, blocked by live wires from four to five power poles knocked to the ground.


Power lines and poles on the ground after violent storm in Falls Church Thursday. (Jane Chicaharito via Facebook)

In Arlington’s Bluemont Park, winds toppled a majestic oak tree. Dennis Dimick, a local photographer, tweeted the “beautiful” tree was “an inspiration and subject of my camera for many years.”

Other pockets of damaging winds blasted suburban Maryland.

The tornado that struck Columbia at 3:34 p.m. was rated EF-1 on the 0 to 5 scale for tornado intensity. It snapped trees and tore the roof off part of a building.

But before producing a tornado, this powerful storm also unleashed intense downburst winds to the west in northern Montgomery County.

“Haven’t seen a gust like that since the derecho,” wrote Chris Hager in Olney at 3:24 p.m. “60 mph easy.”

The Weather Service received a report of 67 mph gust in Gaitherburg, Md. around 3:15 p.m.

The responsible squall line had originated in the Ohio Valley and, on its eastward trek, weakened some as it crossed the Appalachians. But, then, it encountered very warm, humid and unstable air east of Interstate 81 and exploded just as it arrived in the Washington region.

The storm complex was a quick hitter, last no more than about 30 minutes in any one area before sweeping off to the southeast at speeds of 35 to 40 mph.