A series of heavy rainstorms and thunderstorms whipped across the Baltimore metropolitan area, western regions of the state and the Eastern Shore yesterday, knocking down trees and power lines in some areas.
Showers of pea-sized and marble-sized hail were reported in Brooklyn in Anne Arundel County, Baltimore City, Columbia in Howard County, and near Baltimore-Washington International Airport, said Richard Diener, a forecaster at the BWI weather station.
"It was basically a spurt in the system," Mr. Diener said yesterday. "The storms moved through quite quickly, from start to finish, lasting about 20 to 25 minutes."
The thunderstorms that passed through Baltimore and northern and western Maryland were the result of a low-pressure area "that divided the warm, moist, unstable air mass in the region, producing the heavy thunderstorms in the area," Mr. Diener said.
The Howard County Fire Department reported trees and power lines were felled by the storm throughout Columbia.
State Police at the Glen Burnie and Waterloo barracks reported hailstorms, and many county police departments reported minor traffic accidents because of the storm.
A second wave of of thunderstorms hit Washington and Prince George's County around 7 p.m., and moved eastward to the Eastern Shore.
Winds gusting at 50 mph caused the temperature at BWI to drop by 20 degrees -- from 85 to 65 -- around 4:30 p.m. when the storms started, Mr. Diener said. Temperatures stayed in the lower 70s for the remainder of yesterday evening, and will reach the upper 70s today with a 30 percent chance of showers.
But, the storm should lower the high level of "humidity that we've been experiencing in the past couple days," Mr. Diener said.
Because of the storms, 10,000 customers lost electricity in Baltimore and Baltimore, Howard and Anne Arundel counties when trees and lightning struck power lines, said Baltimore Gas and Electric Co. spokeswoman Kathleen Nolan.
About 4,200 customers were affected in Cockeysville, 250 in Glen Burnie, 1,900 in Howard, and 3,700 in Baltimore, Ms. Nolan said.
She said BGE work crews were either working to restore power to customers, or were on their way to the affected areas.
"We're not anticipating any problems restoring power to those areas," Ms. Nolan said.