Violent evening storms have cut power to more than two million people across the eastern United States and caused two fatalities in Virginia, police say.
From Maryland to Ohio, winds topped 112 km/h, damaging homes and uprooting trees Friday night.
The victims in Springfield, Va., include a 90-year-old woman who was killed when a tree slammed into her home and and a man whose car was struck by another tree.
West Virginia Gov. Earl Ray Tomblin declared a state of emergency after more than 500,000 customers in 27 counties were left without electricity.
At least four utility poles fell on a road in Columbus, Ohio, making it too dangerous for people in four cars to get out, police said. One person was taken to a hospital.
As of 1 a.m. Saturday, Pepco was reporting 406,000 outages in the District of Columbia and Montgomery and Prince George's counties, Md.
"We have more than half our system down," said Pepco spokeswoman Myra Oppel. "This is definitely going to be a multi-day outage."
In the Washington, D.C., area, the Metrorail subway trains were returned to their endpoints due to the storms and related damage, officials said.
"It has had a widespread effect on the region," Metro spokesman Dan Stessel said early Saturday. He said about 17 train stations were operating on backup power due to local power outages, but that he didn't anticipate service being disrupted on Saturday.
The storms hit as cities along the coast sweltered in record-setting heat.
Earlier Friday, the nation's capital reached 40 C (104 F), topping a record of 38 set in 1934.