10 dead, mass power outages after thunderstorms in eastern states (UPDATES)

At least 10 people died and nearly 4 million homes across the Midwest and beyond lost power after fierce thunderstorms struck the region Friday night, Fox News reported.

The governors of Virginia, West Virginia and Ohio declared a state of emergency today, which allows them to use all government resources to help residents, according to Fox News.

The Associated Press reported widespread power outages from Indiana to New Jersey, after the storms bore down in the evening and moved east following a day of triple-digit temperatures.

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Washington DC and its surrounding areas – where temperatures Friday topped a record-breaking 104 degrees – was the hardest hit. Elsewhere, by Friday afternoon, the mercury had climbed to 102 degrees in St. Louis, 101 in Richmond, Virginia, and 100 degrees in Indianapolis.

Virginia Gov. Bob McDonnell said the power outage in his state was its largest-ever non-hurricane loss of power, with 2.5 million people affected, Fox News reported.

Utility officials said it could take until next week to restore power to all areas, Reuters reported.

"It's going to be a while before some folks get power, and with the heat, that's our big concern," Bob Spieldenner, a spokesman for the Virginia Department of Energy Management told Reuters.

The National Weather Service (NWS) blamed the high temperatures for bringing lightning and wind gusts as strong as 80mph, CNN reported – adding that the baking heat is expected to continue through the weekend and into early next week.

The "straight-lined windstorm," known as a "derecho," that comes with a band of rapidly moving thunderstorms, knocked down trees and power lines, the BBC reported.

The storm killed two boys, ages 7 and 2, who were sheltering in a tent with family members at a New Jersey campsite early this morning when a tree fell on them, Fox News reported.

Six deaths occurred in Virginia, including that of a 90-year-old woman who was killed when a tree slammed into her home overnight in Springfield. In the same area, a man was killed by a falling tree while driving his car, the AP reported. 

In Washington, a man died when he ventured outside to check on storm damage and was electrocuted by a downed power line, CNN reported.

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Temperatures are expected to soar up to 106 in St. Louis, and excessive heat warnings have been issued through Sunday for eastern Missouri, with the NWS warning that “heat exhaustion or heat stroke are a real threat."