About 50 patients were treated for minor injuries such as cuts from flying glass. Another 14 were treated for more serious injuries that included broken bones and at least seven people who suffered the worst injuries were flown by helicopters to other area medical centers. St. Mary's Hospital in Leonardtown treated five patients for minor injuries suffered when their house collapsed during the storm.
Arthur said the violent weather was triggered by a mass of cold air colliding with warm, moist air.
The typical reaction, she said, is heavy storms with the possibility of tornadoes.
The storms brought heavy rain to Central Maryland, with more than an inch reported at Baltimore-Washington International Airport - continuing the trend of a wet April break in the region's drought.