More than 1M without power as massive winter storm wreaks havoc across U.S.

A massive winter storm has caused thousands of flight cancellations in the United States and left more than 1 million people without power, bringing wind-driven snow, ice and rain to more than half the country.

More than 11,000 flights within, into or out of the U.S. were delayed or canceled Friday, according to the tracking site FlightAware.

According to PowerOutage.Us, a site that tracks utility outages, more than 1.2 million homes and businesses across the United States were without power Friday morning. More than 350,000 outages were reported in New England.

Coastal and river flooding and downed trees and power lines in the tri-state area forced train service to be delayed or canceled.

FedEx issued a warning that holiday packages may arrive late, citing weather delays at its main hub facilities.

According to the National Weather Service, more than 200 million Americans were under some form of winter weather advisory or warning on Friday — the most ever.

Forecasters said bone-chilling air behind the storm system will cause temperatures to quickly plummet by 40-50 degrees in some places. On Thursday, Denver recorded its coldest temperature in more than 30 years: minus 24 degrees.

Forecasters are also expecting a bomb cyclone — when atmospheric pressure drops very quickly in a strong storm — to bring blizzard conditions to the Great Lakes region.

In Buffalo, officials were bracing for what forecasters described as a “once-in-a-generation storm” because of heavy lake-effect snow, high wind gusts and the potential for extensive power outages.

"This is not like a snow day when you were a kid," President Biden warned Thursday after a briefing from federal officials. "This is serious stuff."