Nearly half the United States was caught in an icy blast on Monday, with much of the East Coast bracing for what could be the worst winter storm of the year.
Spring may be around the corner after an unusually warm winter throughout much of the region, but a powerful nor'easter called Winter Storm Stella is forming near the coast as two low pressure systems collide, burying a wide area from the central Appalachians to New England under up to 18 inches (46 centimeters) of snow.
The National Weather Service cautioned that the storm could bring record-low temperatures late Monday into Tuesday, as well as "blizzard conditions in places, difficult travel and power outages."
A blizzard warning was issued for New York, with whiteout conditions expected to make travel "extremely dangerous," according to the weather service. Winter storm warnings were issued for areas from Washington to southern Maine.
Wind gusts of up to 60 miles (97 kilometers) per hour are expected.
"Significant amounts of snow are forecast that will make travel dangerous. Only travel in an emergency. If you must travel, keep an extra flashlight, food and water in your vehicle in case of an emergency," the weather service said.
Hundreds of flights were cancelled ahead of the storm, according to the tracking service FlightAware.
Southwest Airlines warned of cancellations, delays and diversions for Sunday through Wednesday. Delta Air Lines told travelers they could book alternative flights without fees.