Tens of millions of Americans have endured bone-chilling temperatures, blizzard conditions, power outages and cancelled holidays after a winter storm that forecasters said was nearly unprecedented in its scope.The conditions exposed 60% of the US population - more than 200 million people - to some sort of winter weather advisory or warning.The US National Weather Service's map "depicts one of the greatest extents of winter weather warnings and advisories ever", forecasters said.

Tens of millions of Americans have endured bone-chilling temperatures, blizzard conditions, power outages and cancelled holidays after a winter storm that forecasters said was nearly unprecedented in its scope.The conditions exposed 60% of the US population - more than 200 million people - to some sort of winter weather advisory or warning.The US National Weather Service's map "depicts one of the greatest extents of winter weather warnings and advisories ever", forecasters said.