"Unlike a polite hurricane that gives you three days of warning, this storm gave us all the impact of a hurricane without any of the warning of a hurricane," Maryland Gov. Martin O'Malley said.

With the power out, authorities also warned people to be careful when using generators and candles to help light darkened homes.

The bulk of the storm damage was in West Virginia, Washington and the capital's Virginia and Maryland suburbs. At least six of the dead were killed in Virginia, including a 90-year-old woman asleep in her bed when a tree slammed into her home. Two young cousins in New Jersey were killed when a tree fell on their tent while camping. Two were killed in Maryland, one in Ohio, one in Kentucky and one in Washington.

In Washington's northern Virginia suburbs, emergency 911 call centers were out of service; residents were told to call local police and fire departments. Huge trees toppled across streets in the nation's capital, crumpling cars. Cellphone and Internet service was spotty, gas stations shut down and residents were urged to conserve water.