(CNN) This is no ordinary snow storm, weather experts say.

The National Weather Service is using terms such as "life-threatening" and "historic" to describe the system ready to spread across the Northeast.

The storm could dump up to 3 feet of snow in Boston and New York before it ends Tuesday, along with freezing rain and strong wind gusts possibly reaching hurricane level.

Blizzard and winter storm warnings are up from New Jersey through Maine and into Canada.

Airlines began canceling flights by the hundreds. FlightAware, a travel website, put the total at more than 1,800 early Monday

"We plan to cancel all flights Tuesday at Newark, LaGuardia and JFK, as well as Boston and Philadelphia," said United Airlines Spokeswoman Mary Ryan.

Other airlines were implementing similar measures.

Check first if you're flying into or out of the region.

"I want everyone to understand that we are facing -- most likely -- one of the largest snowstorms in the history of this city," said New York City Mayor Bill de Blasio.

He repeated throughout a Sunday afternoon news conference that people should expect delays, very slow or stalled commutes Monday evening. Whatever people do to be cautious, he said, do more.

"My message to all New Yorkers is prepare for something worse than we have seen before. Prepare to be safe. Take every precaution. Now is the time to get ready for this extreme weather," he said. "Don't underestimate this storm."

Photos: Massive storm hammers Northeast Photos: Massive storm hammers Northeast Dexter Newcomb begins cleanup at his house in Scituate, Massachusetts, on Wednesday, January 28, a day after a winter storm left his neighborhood coated in frozen sea spray and sand. Hide Caption 1 of 38 Photos: Massive storm hammers Northeast Cars in Norwood, Massachusetts, sit buried by snow drifts on January 28. The first blizzard of 2015 dumped nearly 3 feet of snow in parts of four Northeastern states. Massachusetts was hit the hardest. Hide Caption 2 of 38 Photos: Massive storm hammers Northeast Workers continue snow removal efforts in the Back Bay neighborhood of Boston on January 28. Hide Caption 3 of 38 Photos: Massive storm hammers Northeast A man battles strong winds in Portland, Maine, on Tuesday, January 27. Hide Caption 4 of 38 Photos: Massive storm hammers Northeast A wave slams into a sea wall in Scituate as evening high tide approaches on January 27. Hide Caption 5 of 38 Photos: Massive storm hammers Northeast Snow piles up at the entrance of a closed T station in Boston on January 27. The city's public transit system was set to reopen the next day. Hide Caption 6 of 38 Photos: Massive storm hammers Northeast U.S. Army soldier Jennifer Bruno carries belongings from her house, center rear, which was heavily damaged by storm surge in Marshfield, Massachusetts. Hide Caption 7 of 38 Photos: Massive storm hammers Northeast Icy water floods a street in Scituate on January 27. Hide Caption 8 of 38 Photos: Massive storm hammers Northeast Snow clings to a man's face as he shovels a sidewalk in Portland, Maine, on January 27. Hide Caption 9 of 38 Photos: Massive storm hammers Northeast A person skis down Memorial Drive in Cambridge, Massachusetts, on January 27. Hide Caption 10 of 38 Photos: Massive storm hammers Northeast Plows clear snow off the Long Island Expressway in Melville, New York, on January 27. Hide Caption 11 of 38 Photos: Massive storm hammers Northeast Plows line up at airplane gates at Bradley International Airport in Windsor Locks, Connecticut, on January 27. Hide Caption 12 of 38 Photos: Massive storm hammers Northeast A worker clears snow in Newtown, Pennsylvania, on January 27. Hide Caption 13 of 38 Photos: Massive storm hammers Northeast Workers clear the platform at the Long Island Rail Road station in Glen Head, New York, on January 27. Hide Caption 14 of 38 Photos: Massive storm hammers Northeast A man clears his snow-covered car on the Upper West Side in New York City on January 27. Hide Caption 15 of 38 Photos: Massive storm hammers Northeast An emergency vehicle drives down a snowy street in Winthrop, Massachusetts, on January 27. Hide Caption 16 of 38 Photos: Massive storm hammers Northeast Fishing boats ride out the storm at a dock in Scituate on January 27. Hide Caption 17 of 38 Photos: Massive storm hammers Northeast A woman walks her dog as snow swirls around the Bunker Hill Monument in Boston on Monday, January 26. Hide Caption 18 of 38 Photos: Massive storm hammers Northeast Snow falls around the Empire State Building in New York on January 26. Hide Caption 19 of 38 Photos: Massive storm hammers Northeast People walk through falling snow in Hoboken, New Jersey, on January 26. Hide Caption 20 of 38 Photos: Massive storm hammers Northeast Two passengers ride a subway car in New York on January 26. Hide Caption 21 of 38 Photos: Massive storm hammers Northeast People look out from office building windows as snow falls in downtown Philadelphia on January 26. Hide Caption 22 of 38 Photos: Massive storm hammers Northeast A man stands in front of a screen listing departing flights at Ronald Reagan Washington National Airport on January 26. Hide Caption 23 of 38 Photos: Massive storm hammers Northeast People cross a street covered in snow in New York's Times Square on January 26. Hide Caption 24 of 38 Photos: Massive storm hammers Northeast As the snow moves in, residents pick up some last-minute items at King's Highway Stop & Shop in New Bedford, Massachusetts, on January 26. Hide Caption 25 of 38 Photos: Massive storm hammers Northeast People walk near Penn Station on New York's Seventh Avenue while a major snowstorm begins on January 26. Hide Caption 26 of 38 Photos: Massive storm hammers Northeast A tugboat sails on the East River in New York on January 26. Hide Caption 27 of 38 Photos: Massive storm hammers Northeast Travelers wait for their train platform to be announced at New York's Penn Station on January 26. Hide Caption 28 of 38 Photos: Massive storm hammers Northeast The New York skyline is seen from Liberty State Park in Jersey City, New Jersey, on January 26. Hide Caption 29 of 38 Photos: Massive storm hammers Northeast A pedestrian passes through Johnstown Central Park in Johnstown, Pennsylvania, on January 26. Hide Caption 30 of 38 Photos: Massive storm hammers Northeast Snow falls on pedestrians in New York on January 26. Hide Caption 31 of 38 Photos: Massive storm hammers Northeast A plane is de-iced at New York's LaGuardia Airport on January 26. Thousands of flights were canceled in anticipation of the storm. Hide Caption 32 of 38 Photos: Massive storm hammers Northeast A man buys a shovel in Winthrop, Massachusetts, on January 26. Hide Caption 33 of 38 Photos: Massive storm hammers Northeast Commuters travel across the Zakim Bunker Hill Bridge into downtown Boston on January 26. Hide Caption 34 of 38 Photos: Massive storm hammers Northeast A cyclist in New York navigates between parked cars and a sanitation truck with a snow plow on it on January 26. Hide Caption 35 of 38 Photos: Massive storm hammers Northeast Passengers talk with a ticket agent at LaGuardia Airport to try to beat the snowstorm on January 26. Hide Caption 36 of 38 Photos: Massive storm hammers Northeast Traffic moves through falling snow near Evans City, Pennsylvania, on January 26. Hide Caption 37 of 38 Photos: Massive storm hammers Northeast A New York City snowplow, loaded with salt, sits in midtown Manhattan as light snow falls on January 26. Hide Caption 38 of 38

The Weather Service says whiteout conditions will make travel extremely dangerous in the entire affected area. Wind gusts in the New York City area could hit 65 mph.

The blizzard warning is in effect from 1 p.m. Monday through Tuesday, with the worst conditions expected from late Monday evening through midday Tuesday.

In Massachusetts, emergency management officials warned that the winter storm will be potentially "historic and destructive."

Snow in the southeastern part of Massachusetts could morph into a period of freezing rain. And a major nor'easter is likely to develop on Monday and move up the northeast coast, forecasters said.

Travel across Massachusetts during the storm could be impossible and life-threatening, according to the Massachusetts Emergency Management Agency. It's unclear just how much snow might be on the way, but the National Weather Service is saying 1 to 2 feet is possible.

The Rhode Island Emergency Management Agency tweeted Sunday that the state would be under a blizzard watch Monday.

That area's storm conditions aren't predicted to let up until Wednesday morning.

Christine Carew, a sales associate in Boston, said customers have been coming into the hardware store to grab last-minute snow supplies.

Parents and their children have popped in to buy sleds and others are picking up shovels, ice melt and snow brushes.

"This is kind of typical," she said about Boston getting a lot of snow. "We're more prepared for it. We know it's going to happen."

Blizzard Watch issued for RI to be in effect Mon night to Tues night due to predicted snow accumulations of 18-24" http://t.co/v1635ezsLy — Rhode Island EMA (@RhodeIslandEMA) January 25, 2015

There's little chance the store will be closed Monday, no matter how hard it snows. The manager, she said, lives above the store.

Eight counties in Massachusetts are already under a winter storm watch: Berkshire, Franklin, Hampshire, Hampden, Worcester, Barnstable, Nantucket and Dukes.

A blizzard watch is in effect for Essex, Middlesex, Suffolk, Norfolk, Bristol and Plymouth counties. Barnstable, Nantucket and Dukes counties also face a high wind watch.

Derek and Jim Missert have lived in the Boston area for years. On Sunday they prepared to ride out the storm by being as prepared as they usually are, with plenty of food and water on hand. Jim Missert lives outside the city, so he expects to lose power and has a generator. Derek Missert expects that he'll not lose electricity as he works from home in the city.

There could be coastal flooding in the state starting early Tuesday with pockets of major flooding on east-facing coastlines, the state emergency agency said.

New York Gov. Andrew Cuomo urged New Yorkers to prepare immediately for the storm, saying they should plan for "major disruptions" during Monday and Tuesday morning commutes. Roads could be closed and power could go out, he said in a news release Sunday, and New Yorkers need to look out for downed power lines and tree limbs.

Update: NYC is now under a Blizzard Watch for Monday afternoon through Tuesday evening, per @NWSNewYorkNY: http://t.co/AuYng7bMk5 — NYC OEM (@nycoem) January 25, 2015

Cuomo directed all state agencies to prepare. New York has at least 1,806 plows and more than 126,000 tons of salt to spray on roads across the region. The National Guard will also have six dozen personnel and 20 vehicles stationed throughout the state starting on Monday morning.