UPDATE 2-U.S. Northeast digs out of monster snowstorm

* Storm goes to sea after dumping 2 feet (70 cm) of snow

* Snowy streets, airport delays stymie travelers

* Federal government in DC to be closed on Monday (Adds Federal government closed in DC on Monday, paragraph 6)

By Chris Michaud

NEW YORK, Dec 20 (Reuters) - The U.S. Northeast began digging out on Sunday from a massive snowstorm that buried cities from Washington to Boston under as much as 2 feet of snow, creating travel chaos and hampering Christmas shopping.

Nearly 2 feet (70 cm) of snow piled up in the Baltimore-Washington area on Saturday in the largest snowstorm to hit the region since February 2003, while New York City saw totals of up to a foot (35 cm) before the monster storm churned into New England.

Boston, Cape Cod and southeastern Massachusetts areas saw as much as 2 feet of snow before the storm moved out to sea. Areas of eastern Long Island had blizzard-like conditions and nearly 2 feet of precipitation.

The storm gave Washington its snowiest December on record, said Weather Channel meteorologist Mike Seidel.

"After six winters here in Washington of sub-par (below average) snowfall ... we picked up a whole season's worth in one storm," Seidel said. The average for a season is just under 16 inches (41 cm).

Federal government agencies will be closed on Monday as the U.S. capital continues to emerge from the snow.

Washington-area airports were hit with significant delays and cancellations, as were New York's three metropolitan airports, which remained opened. Airlines canceled hundreds of flights, with few planes either arriving or departing.

Washington's Reagan National airport shut down on Saturday and reopened about midday on Sunday.

The driving snowstorm did not stop the U.S. Senate from convening and working on legislation to reform U.S. healthcare.

In New York, Broadway shows went on with Mayor Michael Bloomberg urging residents to enjoy the city's cultural institutions and take advantage of ticket cancellations for hot shows.

'SHOPPER STOPPER'

The storm also took a bite out of retail sales on one of the busiest shopping weekends of the year as Christmas looms.

Washington Mayor Adrian Fenty declared a snow emergency and asked District of Columbia residents to keep off the streets as the U.S. capital faced what one TV station dubbed "The Shopper Stopper Storm."

Washington closed above-ground operations of its subway and stopped all bus services by early afternoon Saturday because streets were rapidly becoming impassable.

In New York City, where totals ranged from about 6 inches (15 cm) to a foot (35 cm), Bloomberg said, "The snow coming in later yesterday than forecast was a godsend for the stores," which reported only small downticks in business on Saturday.

New York subways remained running and its public schools were expected to be open on Monday. Long Island Rail Road service was extremely limited on Sunday, a spokesman said.

Amtrak trains experienced cancellations, a reduced schedule and delays, with seats at a premium as holiday travelers sought alternatives when air travel was severely disrupted.

Motorists across the region were urged to stay off treacherous roads and several main arteries were closed. In Washington, drivers who ventured out often had to abandon their cars due to deep snow on the streets.

The storm halted transportation in the Boston area, with dozens of flights canceled at Logan Airport, which had only one runway open. Traffic picked up later in the day as the snow slowed and flights began to trickle in from up and down and the East Coast.

At least one person died in the storm. The Virginia Department of Emergency Management said a 68-year-old woman died in a car crash in southern Virginia on Friday night.

(Additional reporting by Jim Finkle in Boston and Toby Zakaria in Washington; editing by Sandra Maler)