Light snow began falling on the US East Coast on Monday morning, the first signs of a potentially historic blizzard that officials predicted would dump up to 90 cm of snow in the coming day, snarling transportation for millions of people.
Airlines have cancelled more than 2,300 flights so far, according to flight-tracking service FlightAware, with more than 600 alone at the three main airports serving New York City.
The US National Weather Service (NWS) issued a blizzard warning for New York City and surrounding areas between coastal New Jersey and Connecticut, beginning 1 pm EST (1800 GMT) on Monday and worsening overnight into Tuesday morning. It warned of two days of winter storms across the East Coast, from Pennsylvania to Maine.
Travel will be extremely dangerous, said the service, as strong snow-filled winds reduce visibility to near zero.
New York City Mayor Bill de Blasio has warned of potentially “the biggest snowstorm in the history of this city”, urging residents of the US financial capital and most populous city to stay off the roads.
New York Governor Andrew Cuomo urged people to work from home, saying the city's bus and subway systems could be closed ahead of Monday's evening commute, along with the Metro North Railroad, the Long Island Rail Road and other commuter rail services.
In Connecticut, Governor Daniel Malloy told residents that bus service statewide would shut down by 8 pm
EST (0100 GMT Tuesday), and that a travel ban would be in place to keep drivers off roads.
US President Barack Obama, who is in New Delhi, was briefed on the coming storm earlier on Monday, White House spokesman Josh Earnest told reporters.
The NWS called the approaching system a “crippling and potentially historic blizzard”, with many areas along the East Coast expected to be blanketed by 30-60 cm of snow.
The New York City area could be the hardest hit, with lashing winds topping 81 kmph and snowfall of 76 cm or more in some suburbs.
The biggest snowfall on record in New York City came during the storm of February 11-12, 2006, dropping 68 cm, according to the city's Office of Emergency Management.
Cities along the heavily populated East Coast had snow-ploughs and trucks on standby to dispense road salt.
