Thunderstorms brought strong gusts, lightning and rain across the Washington region, causing power outages and injuries at outdoor activities.

Forecasters had issued storm watches for much of the area Sunday. A National Weather Service (web|news) spotter reported penny-sized hail at Fort Meade.

Local power companies also had thousands of customers without power Sunday afternoon. As of 6 p.m., Pepco reported a total of 5,400 outages in the area. Dominion Power reported a total of 1,232 outages in Northern Virginia and BGE reported a total of 61 outages in Montgomery and Prince George's County's. 

The weather posed dangerous conditions for outdoor festivities taking place around the region.

At a festival at Fairview Beach on the Potomac River, boats were hit by four-foot waves as storms moved through. Crews from the Coast Guard, Charles County and Prince George's County rescued several people from the water.

Fairfax County (web|news) officials say three people suffered minor injuries after a tent they were under collapsed at Bull Run Regional Park in Centreville. Police say crowds ran to the tent as it began to rain at a festival. A child and two adults were hospitalized with  injuries after being hit.

Event coordinator, John Olaya, told ABC 7/NewsChannel 8 reporter, Brianne Carter that one of the storm victims had to get stitches, but most of the injuries were minor.

Officials say hundreds of people were at the Peruvian festival when the treacherous weather rolled in. Maria Cake was there to watch her daughter's dance team perform. She chose to wait the storm out in her car. "Our instructor told us to stay in our cars...," said Cake.

Authorities say lightning struck a chimney at a house in Fairfax Station, causing part of the chimney to fall on a gas meter, which started a minor leak.  

 Montgomery County (web|news) authorities reported lightning struck a house in Clarksburg, causing a fire and $100,000 in damages. In another incident, a tree that was hit by lightning in Clarksburg also started a brush fire, causing a shed to catch fire.

A woman was brought to a Silver Spring fire station with burns and wounds consistent with being struck by lightning, officials said. She was taken to a hospital with serious injuries.