Residents from Virginia to New York prepared for a major snowstorm that could bring 12 inches (30.5 cm) of snow just days after a blizzard dumped up to 3 feet (90 cm) in some areas.

American Airlines cancelled Wednesday flights in and out of Washington's three area airports as well as Philadelphia. Late flights on Tuesday were also cancelled so that planes are not stranded in the snow, the airline said.

Carriers have relaxed their ticket policies to allow passengers to change flight plans around the storm. Both moves could cloud the outlook for an industry already hard hit by the battered economy.

US Airways cancelled its hourly shuttle service between Washington and New York for Wednesday while Amtrak passenger rail service warned of limited service along its Northeast corridor.

US government offices in Washington closed on Tuesday for a second straight day -- at a cost of roughly USD$100 million in lost productivity a day -- and forecasters were predicting the US capital could get upwards of 20 inches (51 cm) by Wednesday night.

Residents have spent the last few days trying to dig out from the snowfall that dropped 18 inches (46 cm) to 32 inches (81 cm) last weekend from Washington to southern New Jersey, as well as trying to clear fallen trees and re-stock their refrigerators.

There still are more than 15,000 customers without power in the Washington metropolitan area while subway and bus services were scaled back. The US House of Representatives cancelled votes for the rest of the week and many congressional hearings were called off.

Beyond the US capital, preparations were under way for 10 (25 cm) to 18 inches (45 cm) in Philadelphia and 8 (20 cm) to 13 inches (33 cm) in New York City, according to the National Weather Service.

Forecasters also were predicting strong winds that could cause additional power outages.