Up to nine people have been killed and and at least 3.9m homes and businesses have been left without power after thunderstorms downed power lines in the US.
Statewide emergencies were declared in Washington D.C., Ohio, Virginia and West Virginia because of damage from overnight storms.
Hurricane force winds were said to have occurred along a 500-mile stretch.
Forecasters have predicted more thunder storms with renewed heat today.
Restoring power in some areas could take up to a week.
The widespread power outages came as the National Weather Service forecast more heat and severe thunderstorms across the Ohio Valley and into the northern mid-Atlantic states.
US State and local officials urged residents to seek air-conditioned areas.
They have urged people to drink lots of water and wear light-coloured clothing.
