Officials say quick response is paramount especially since the region is currently baking in triple-digit temperatures.
From Indiana to New Jersey and south to Virginia, officials warned the heat wave could take a toll on the elderly, young or sick.
Emergencies have been declared in Virginia, Maryland, West Virginia, Ohio and the District of Columbia. Virginia Gov. Bob McDonnell said the state has had its largest non-hurricane outage in history.
Virginia was one of the hardest hit states. At least six died there, including a 27-year-old father of two who was driving at the height of the storm
In total, the vicious storms killed at least 13 people and left three million people in the dark. Power officials say outages won't be repaired for several days to a week.
The Associated Press contributed to this report.