Residents in the northeastern United States braced for worsening conditions overnight, as forecasts predicted a further drop in already below-freezing temperatures.

The storm - named Hercules - left at least 11 people dead on Friday, as snow and strong winds swept down from Canada into the northeastern United States. Most of the deaths were attributed to traffic accidents.

One of the fatalities occurred in Philadelphia when a worker was crushed by a pile of road salt. An elderly woman suffering from Alzheimer's disease also died on Friday when she wandered away from her home in New York state.

The governors of New York and neighboring New Jersey declared states of emergency and urged residents to avoid leaving their homes.

"This is nothing to be trifled with," New York Gov. Andrew Cuomo said. "People should seriously consider staying in their homes."

The mayor of New York City, who was sworn in on Wednesday, also urged caution.

"If you want safe, clear streets, stay home," Mayor Bill de Blasio said.

Both New York City and Philadelphia reported roughly 6 inches (15 centimeters) of snowfall. Essex County, which lies just north of Boston, received 2 feet of snow.

Cancellations and closures

Airports in Boston, Philadelphia, New York and Washington, D.C. experienced major flight disruptions with over 2,200 cancellations by Friday midday.

The storm cell began passing through on Thursday, prompting school closures and the deployment of snow ploughs and salt spreaders. Workers at state offices were also sent home early on Thursday.

The National Weather Service has issues blizzard warnings for Cape Cod, coastal areas north and south of Boston, and parts of Maine and New York's Long Island. Up to 25 centimeters of show is expected to fall, while forecasters predict wind gusts of up to 72 kilometers per hour (45 miles per hour) across the region.

kms/ccp (AP, AFP)