SNOW and icy rain has pelted the US east coast, with forecasters warning the “historic early season” storm could dump up to a foot (30cm) of snow in some areas.

The rare October snowstorm was wreaking havoc on air and road traffic from Washington to Boston, with the National Weather Service warning that travel at night would be “extremely hazardous.”

Air travellers were seeing an average delay of six hours on flights to and from Newark International Airport, the Federal Aviation Administration said. Similar problems were affecting New York’s Kennedy international airport.

Forecasters issued a winter storm warning for large parts of the northeast, predicting heavy snow, freezing temperatures and strong winds with gusts up to 60 miles per hour (100 km/ph).

Up to a foot of snow was expected in parts of Connecticut and New Jersey, the weather service said. In Manhattan, forecasters said up to 10 inches (25cm) could fall.

Trees that have yet to shed their leaves toppled from the weight of the snow and knocked out power to thousands of homes, the National Weather Service said.

Unseasonably cold air was pouring into the northeast, and deep tropical moisture was set to surge northward along the east coast and “fuel an expanding area of heavy rain and snow”.

Much of the region was socked in August by Hurricane Irene, whose heavy rains and wind left millions without power, destroyed homes and caused record flooding. More than 40 people died.