Emergency services are seen working and covering the Subway vent to prevent flooding on November 07, 2012 in New York City. [CFP]

Gusting winds, rain and snow from Wednesday's northeaster has disrupted traffic and cut power supply in New York and New Jersey, which are still recovering from Superstorm Sandy.

New York Mayor Michael Bloomberg said the biggest concern for the city was for low-lying areas in Zone A, where trees were weakened by Sandy and sand that would have acted as a barrier was washed away.

Police in those areas made announcements to ensure elderly or homebound residents and those with infants have a safe place to go, but evacuations were not mandatory.

By early Thursday, more than 292,700 homes and business in New York state were without power, and another 403,000 in New Jersey lacked electricity, according to local media reports.

The Long Island Rail Road was suspended during the storm and but has resumed by Thursday.

Under ordinary circumstances, a storm of this sort wouldn't be a big deal. But large parts of the landscape were still an open wound, with the electrical system highly fragile and many of Sandy 's victims suffering from the deepening cold.