Shell station owner Chi Li said his employees ran for cover when high wind gusts came through around 4:30 p.m., knocking out power.
The storm caused similar problems at Belisimos Italian restaurant, which had to close early.
"We would like to stay open, but we don't have anything to serve people," said manager Sean Storm.
The National Weather Service first issued a tornado watch for Western Maryland about 1:30 p.m., and it was quickly extended to the rest of the state. It was the first significant outbreak of severe weather in Maryland during a spring that has been less kind to parts of the Midwest and Tennessee and Ohio valleys. Tornado warnings were reported in central Virginia, Waldorf in Southern Maryland and around the Baltimore area in a flurry of about three hours as the system passed through.