Weather forecasters on Sunday put the U.S. East Coast from New York City to Boston on a blizzard watch, warning of the potential for 12 to 18 inches of snow and wind blasts in some areas from Monday night into Wednesday.
New York City issued a snow alert for Monday night, preparing its fleet of snow plows, as some 50 million people up and down the Eastern Seaboard came under winter storm or blizzard watches.
Washington, which often bogs down with even low levels of snow, was expecting 5 inches in the city and twice that in outlying areas.
The storm raised the potential for dangerous travel and power outages with damaging wind gusts up to 50 mph possible across eastern Long Island and southeastern Connecticut, the National Weather Service said.
The likelihood of blowing snow and strong winds could lead to "whiteout" conditions with visibility as poor as a quarter mile, the service said. Sub-freezing temperatures were forecast in the upper 20s Fahrenheit.
New York state Governor Andrew Cuomo announced preparations for the so-called Nor'easter storm, activating the state Emergency Operations Center as of Monday night while also directing state agencies to be on heightened alert.
"I encourage all New Yorkers in affected regions to plan ahead, and avoid any unnecessary travel as the storm progresses," Cuomo said in a statement, adding that commuters should expect road closures, delays and cancellations.
The Port Authority of New York and New Jersey was installing hundreds of pieces of snow equipment at the three New York area airports, including snow melters that can liquefy up to 500 tons of snow per hours and plows that can clear snow at 40 mph, Cuomo's office said.
Thousands of tons of salt and sand were prepared for airport roads, parking lots, bridges and tunnels.
The threat of heavy snow comes toward the end of an unusually mild winter along much of the East Coast, with below-normal snowfalls in some areas, including New York City and Washington. It was the warmest February on record in nearly the entire area, according to the Northeast Regional Climate Center.
Last week in New York, temperatures hovered near 70 degrees Fahrenheit, according to Accuweather.com, and hit 60 degrees or higher on six days in February.Try Newsweek: Subscription offers