New York, Jan 27 (Agencies) : A massive, wind-whipped blizzard slammed into the US Northeast on Monday, creating havoc for more than 60 million people and forcing New York City to shut down on a scale not seen since Superstorm Sandy devastated the region in 2012.

The potentially historic storm which could affect 20 percent of the US population, caused at least six states up and down the East Coast to declare emergencies, forced the cancellation of thousands of flights, closed major mass transit hubs and schools.

The National Weather Service (NWS) warned that the "life-threatening blizzard" could dump a "crippling snowfall" of as much as 3 feet (90 cm) on the region.

Coastal flood warnings were issued, with tides in the New York metro area expected to be as much 3 feet higher than normal early Tuesday morning.

States of emergency were declared in New York, New Jersey, Connecticut, Rhode Island, Massachusetts and New Hampshire as people were urged to stay home with transit systems, including the New York City subway, suspending services and roadways closed amid white-out conditions.

New York Governor Andrew Cuomo announced a travel ban for all but emergency vehicles on every road in 13 counties in southern New York state, including New York City, suburban Westchester and Long Island, with the threat of a $300 fine for violators.

His peers in Connecticut and Massachusetts imposed similar bans on driving.

DRIVING IS A CRIME

"If you are in your car and you are on any road, town, village, city, it doesn`t matter, after 11 o`clock, you will technically be committing a crime," Cuomo said. "It could be a matter of life and death so caution is required."

The storm also poses the latest challenge to New York City Mayor Bill de Blasio, who has been under fire in recent weeks from police who criticized his support of public protests about white police violence against black men. In the last major storm de Blasio was vilified for keeping schools open.

The NWS issued a blizzard warning from New Jersey to Maine, with conditions worsening overnight and wind gusting to over 50 mph (80 kph) in the New York City area.

With Boston expected to bear the brunt of the storm with near hurricane force winds predicted on Tuesday, Mayor Martin Walsh urged residents to report homeless people who need shelter, check on elderly neighbours and stay inside for the duration of the blizzard.

Retailers ran short of everything from shovels and snowblowers to basic groceries. At a Shaw`s Supermarket in Somerville, Massachusetts, canned food shelves were thinned and checkout lines long. In Brooklyn, grocery store shelves were stripped of bread and bottled water.

"I`ve been to three or four stores and I can`t get any milk or eggs," said Marcy Rivers, waiting in the snow for a bus in Bridgeport, Connecticut. "I don`t know what we are going to do now."

SUBWAY SHUTDOWN

The brutal weather paralysed the New York City metropolitan area, with an 11 pm deadline set for suspending all subway, bus and commuter rail service on Metro-North Railroad and Long Island Rail Road.

While New York`s subway system has shut down ahead of major tropical storms, such as 2012`s devastating Superstorm Sandy, transit officials said this was the first time they had cancelled service solely due to snow.

New Jersey Transit said on its website it halted commuter trains and buses late on Monday and would not resume service until "conditions permit."

Amtrak suspended service on Tuesday between New York and Boston, and into New York state, Vermont, Massachusetts and Maine.

Vacationers and business travellers faced headaches as airlines cancelled around 3,000 US flights, with Boston and New York airports most heavily affected, according to flight-tracking service FlightAware. New York authorities also said "virtually all" flights at LaGuardia Airport on Tuesday will be cancelled and cancellations at John F Kennedy International Airport will be "significant."

SCHOOLS CLOSED

The blizzard knocked out entertainment events including Monday night Broadway performances and home games for the New York Knicks and Brooklyn Nets and shut New York City`s zoos, where snow leopards, puffins and polar bears frolicked in privacy.

The United Nations headquarters gave itself a day off on Tuesday. East Coast schools, including New York City with the nation`s largest public school system serving 1 million students, and universities, including Harvard and the Massachusetts Institute of Technology, cancelled classes for Tuesday.

"The beauty of this snowstorm is I have midterms this week," said Oliver Stoller, 13, after his school in Maplewood, New Jersey, was cancelled for Tuesday and he spent Monday night turning his neighbourhood sidewalk into a sledding path.

Wall Street traders rushed home early on Monday, although exchanges remained open.

The biggest snowfall on record in New York City came during the storm of Feb 11-12, 2006, dropping 26.9 inches (68 cm), according to the city`s Office of Emergency Management.