BOSTON • The fiercest snowstorm of the winter has slammed the north-eastern United States, leaving 30cm of snow in places, leading to thousands of flight cancellations and shutting down schools.

At least two deaths were blamed on the storm.

The storm, which came a day after temperatures had been a spring-like 10 to 16 deg C, had wind gusts up to 80kmh and left roads and pavements dangerously slick in densely populated cities like New York, Boston and Hartford, Connecticut. The winds reached as far south as Virginia, where a truck driver died after his tractor-trailer was blown off the Chesapeake Bay Bridge-Tunnel, said the facility's deputy director Tom Anderson.

A New York City doorman died while shovelling snow as he slipped and fell down a flight of stairs, crashing into a window that cut his neck, police reported.

Some areas experienced "thunder snow", violent bursts of weather featuring both snow and lightning.

Nearly two-thirds of flights into or out of the three major New York-area airports were cancelled, as were 69 per cent of those at Boston Logan International Airport, according to Flightaware.com. Nationwide, about 4,000 flights were cancelled and 5,700 delayed. "The roads are dangerous," New York Governor Andrew Cuomo told reporters. "If you don't have to be out, don't be out."

New York received about 30cm of snow, while Boston was bracing itself for up to 50cm. Many schools systems were closed in the area, and Boston schools would remain closed yesterday, Mayor Marty Walsh said.

Many government offices also were shuttered, with Massachusetts and Connecticut ordering non-emergency workers to stay at home. Blizzard warnings were in effect for New York's eastern Long Island suburbs, southern Connecticut and Rhode Island, as well as the Massachusetts coast.

REUTERS