From Staff Reports

A line of powerful thunderstorms swept into the Washington area from the west this afternoon, bringing lightning, hail, heavy rain, strong winds and cutting power to more than 100,000 people.

The National Weather Service issued a severe thunderstorm watch for the region through 9 p.m. and a number of thunderstorm warnings were posted. Check for latest updates and alerts at the Capital Weather Gang.

Three adults and seven children were slightly injured on the Mall when one of the tents being erected for the annual Smithsonian Folk Life Festival was whipped by the wind and buckled and the tent's metal tubing hit them, said Alan Etter, a spokesman for D.C. Fire and Emergency Medical Services. All the injuries were minor, Etter said, but the 10 people were transported to a local hospital.

Weather service spotters reported trees and powerlines down and hail up to one-inch in diameter in Loudoun County. Drenching rain hit the District shortly after 4 p.m. Gusts of more than 60 mph hit parts of Alexandria and Washington Nationals Stadium in the District.

Pepco said more than 25,000 customers were without power for a brief time. But the Northern Virginia suburbs were hit harder. Dominion Virginia Power reported more than 100,000 customers in the dark in Northern Virginia before 5 p.m. By 8 p.m. the number dropped to under 85,000.

The storm was moving southeast at about 33 mph, according to forecasters, but more storms could develop through the evening.