A winter storm has slammed the US Northeast, forcing Boston to delay the Superbowl victory parade for the New England Patriots.

The second major storm in less than a week has pummelled New York City through to Boston with snow, freezing rain and gusty winds.

The storm also dumped more than a foot of snow in parts of the Midwest.

In Massachusetts, a woman was struck and killed by a snowplow at a condo complex, while two people were killed in a highway accident in Indiana.

Police said hazardous road conditions caused by the storm may have been a contributing factor.

Boston, already buried under 2ft of snow, prepared for more heavy snowfall - prompting Mayor Marty Walsh to postpone the Patriots' parade by one day.

"We look forward to celebrating with Patriots fans during better weather on Wednesday," Mr Walsh said in a statement.

But it wasn't all bad news - two Irish men managed to sneak into the University of Phoenix Stadium and watch the game for free.

The snow also delayed until Wednesday jury selection for the federal trial of the accused Boston Marathon bomber, Dzhokhar Tsarnaev.

Up to 6in of snow was forecast for New York City, where snow and ice caused a crowded subway train to stall on an elevated stretch of track for more than two hours.

Six more weeks of winter

The storm stretched as far south as Philadelphia, pummelling millions of morning commuters with freezing rain, snow and gusty winds.

More than 5,300 flights have been cancelled over Sunday and Monday, according to flight tracking service FlightAware.

In and around Chicago, residents were forced to shovel out after more than a foot of snow fell across the area.

As if on cue, the storm moved east just in time for groundhog Punxsutawney Phil to predict six more weeks of winter.

The National Weather Service warned residents of Massachusetts, Vermont, New Hampshire, Maine, Rhode Island and northern Connecticut to expect as much as a foot of fresh snow from the "potent" storm.

Crews in Maine, where nearly 3ft of snow fell last week, struggled to cope with the fresh accumulation.

"Road crews have been up all night making room for the next round. There's just no place to put it all," said Betty Case, town clerk in coastal Lubec, Maine.

The National Weather Service warned of "dangerous wind chills" through the coming days.