A sprawling winter storm has grounded more than 14,500 flights around the U.S., halted trains and triggered a grid emergency and knocked out power to thousands, all while threatening to drop a foot of snow on New York City and the rest of the Northeast corridor on Sunday.

As of 5:30 p.m. New York time, 14,537 flights across the U.S. were grounded through Monday, reaching levels not seen since the government shutdown last year, airline tracking company FlightAware said.

Meanwhile, more than 118,000 homes and businesses from Colorado to the Atlantic were without power, with almost 102,000 of them in Texas and Louisiana, PowerOutage.us said. Early Saturday, the Midcontinent Independent System Operator ¡ª which manages a power grid that stretches from the Great Lakes to the Gulf Coast ¡ª declared an energy-emergency alert 2 in an effort to shore up reserves as conditions worsened.