Updated

Tens of millions of Americans braced Monday for what could be the biggest storm to slam the Northeast this winter, threatening to snarl Spring Break travel plans as it is forecast to dump upwards of 2 feet of snow through the region.

AIRLINES CANCEL MORE THAN 1,500 FLIGHTS AHEAD OF LATE WINTER STORM

The National Weather Service issued a blizzard warning from late Monday night through Tuesday evening from the Philadelphia suburbs through New York City and Boston to Maine. Winter storm warnings stretch through the remainder of the region.

Meteorologists said the storm could bring 20 inches of snow in New York City, and up to 24 inches north of the city, as well as eastern Pennsylvania and northern New Jersey into New England.

The weather service's office near Philadelphia called the storm "life-threatening" and warned people to "shelter in place."

The storm could also pack wind gusts of 40 to 50 mph -- the latest frustration for a town in upstate New York that felt winds so strong, they covered a house in ice. John Kucko said the winds lashed lake water on the home in Webster, and he posted photos and video of the frozen house over the weekend.

ICE HOUSE FORMED BY STRONG WINDS, FREEZING TEMPERATURES IN NY

"This would certainly be the biggest snowstorm of the 2017 winter season in New York City," NWS meteorologist Faye Barthold told Fox 5. Major airlines have already canceled more than 1,000 flights ahead of the storm.

Mayor Bill de Blasio said Monday that New York City schools would be closed Tuesday, and he urged residents to avoid unnecessary travel and help keep the roads clear for sanitation crews and first responders.

"We're preparing for a significant storm on Tuesday, and New Yorkers should also prepare for snow and dangerous road conditions," de Blasio said.

New York Gov. Andrew Cuomo said above-ground services from New York City's main transit agency will stop running at 4 a.m. Tuesday because of the upcoming winter storm.That means no service on the portion of the New York City subway system that runs above ground.

Cuomo said service on the Long Island Rail Road and Metro-North commuter lines could also be "significantly impacted."

Cuomo is urging people to stay home — and off the roads — unless absolutely necessary. He added there are currently no plans to cut underground Metropolitan Transportation Authority service, though he added "given the severity of the storm, anything can happen."

A state of emergency in New York will begin Tuesday morning, immediately after midnight.

Light snow is expected to begin late Monday night and intensify overnight into early Tuesday morning.

Snowfall rates as much as 2 to 4 inches per hour are expected on Tuesday.

"This would certainly be the biggest snowstorm of the 2017 winter season in New York City," said Faye Barthold, a Long Island weather service meteorologist.

Boston also could potentially receive 12 to 18 inches, with isolated amounts of up to 2 feet across Massachusetts.

The Massachusetts Emergency Management Agency has been prepping equipment, with dangerous travel conditions a primary concern as snow could fall at times at a rate of 3 inches an hour, FOX 25 Boston reported.

Hundreds of pieces of equipment will be on the states roads and highways before, during and after the storm.

“Sometimes even when there's a lot of plows out on the road, we can have trouble keeping up with that. So trying to keep people off the road is number one and again, making sure people are aware of power outages,” a MEMA spokesperson told FOX 25.

In Philadelphia, where up to a foot of snow could fall, crews began treating some area roadways on Sunday. City school will be closed Tuesday, and officials declared a snow emergency will go into effect at 9 p.m. Monday night, according to FOX 29.

Farther south in the nation's capital, where the National Cherry Blossom Festival is scheduled to start Wednesday, snow accumulations of 6 to 8 inches are expected.

Washington D.C. Mayor Muriel Bowser said more than 200 snow plows will be deployed by Monday night and roads have been pretreated. A decision on the status of D.C. Public Schools will be made by 5 a.m. Tuesday, Fox 5 DC reported.

Connecticut Gov. Dan Malloy issued a statewide travel ban in effect beginning at 5 a.m. Tuesday in effect until further notice.

As the East Coast prepared for the massive storm, the Midwest was hit with snow Monday, forcing a number of flight cancellations. In Chicago, the forecast called for 3 to 6 inches of snow, the city's first significant snowfall since mid-December.

Southern portions of Minnesota got more than 9 inches of snow in some areas. In Michigan, utility crews worked in the snow to restore power to those still without electricity following high winds that hit the state on Wednesday.

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The Associated Press contributed to this report.