"Aug. 15 ó The largest blackout in North American history slowly receded early Friday, with power returning in fits and starts to affected areas in the Northeast, Midwest and eastern Canada. Officials on both sides of the border were struggling to understand what had caused the power system to fail, and more importantly, why the disruption spread so rapidly across such a wide area, cutting electricity to as many as 50 million people."
The Niagara power plant was the root of problem... It couldn't handle all the devices running at once... The Niagara power plant branches off to several locations of North America.
Anyway just spreading word for those who don't know about it.