* Virginia calls out National Guard
* 2,200 flights canceled, half at DC, NY, Phila. airports
* Chicago gets 9 inches of snow
* Washington untouched, weather advisories canceled (Updates to add that the federal government will be open on Thursday)
By Ian Simpson
WASHINGTON, March 6 (Reuters) - A major snowstorm blanketed the Appalachian Mountains on Wednesday, leaving 150,000 homes and business in nine states without power, but Washington got mostly rain after officials had shut down the U.S. capital as the storm approached.
About three inches (7.5 cm) of snow hit Washington's Dulles airport, and by late afternoon only light rain was falling on the capital's streets. They were largely deserted after the federal government ordered its 375,000 workers in the area to stay home.
The National Weather Service called off winter weather advisories for Washington, after warm Atlantic air lessened the storm's impact in the capital area, said meteorologist Brian Lasorsa.
"There's no winter weather advisory, no watch, warning, nothing. Everything from that end is canceled," he said.
Government agencies will be open for business on Thursday, the federal Office of Personnel Management said in a statement.
The National Weather Service posted storm warnings earlier on Wednesday for much of the Ohio River Valley and the mid-Atlantic states and as far south as eastern Tennessee, while Virginia declared a state of emergency.
The storm had been dubbed "snowquestration" by Washington wags in a nod to the battle over the federal budget sequester. It had been predicted to be the biggest in the capital area in two years.
Schools, some congressional hearings and many businesses and institutions in Washington shut down as the storm rolled east after pummeling the Midwest.
The State Department and White House called off regular press briefings because of the threatened snowfall. The White House said foul weather could postpone a dinner between Democratic President Barack Obama and Republican senators called to help revive budget talks.
Virginia Governor Bob McDonnell declared a state of emergency as wet, heavy snow and rain fell across the state. State police had fielded more than 367 calls about traffic accidents and 237 about stalled vehicles since midnight, and the National Guard was activated, he said in a statement.
Airlines canceled some 2,200 flights, with about one-half at Washington, Philadelphia and New York area airports. About 149,000 homes and businesses were without power across nine states.
The heaviest snowfall, 14.8 inches (37.6 cm), was recorded at Sugar Grove, West Virginia. The system dumped 9 inches (23 cm) on Chicago's O'Hare International Airport, in the city's biggest snowstorm in two years, the weather service said.
Coastal flood warnings were in effect for part of the Atlantic coast from Maryland north to New York's Long Island. Authorities in Brick Township, on New Jersey's shore, urged residents in flood-prone areas to evacuate.
Brick Mayor Steven Acropolis said many residents were still unnerved by the pummeling from Hurricane Sandy in October.
"A lot of people just don't want to stay in their home again and hear the wind blowing, and hear the rain coming and not know (if), 'Boy, am I going to get flooded out again?'" he said.
Monique Bond, a spokeswoman with the Illinois State Patrol, said bad weather may have contributed to a crash that killed a woman and her child on highway Interstate 70 in Marshall, Illinois.
In Washington's Maryland suburbs, a group of children were surprised to hear that school was canceled because there was not any snow.
Jason Kaplan, 10, engaged friends in a snowball fight.
"It's good packing," he said. But when they dragged sleds and inner tubes to sledding hills, he and his friends found only slush.
"There was a lot of mud," he said.
The heavy snow shut down at least 500 schools in central and southern Ohio, including the University of Cincinnati.
The ad hoc Washington Snowball Fight Association moved back its scheduled snowball fight from the afternoon to the evening, citing lack of accumulation. "Thanks for keeping the faith!" it said on its Facebook page. (Additional reporting by Scott DiSavino, Patrick Rucker, Kim Palmer, Diane Bartz, Dave Warner and Lesley Wroughton; Editing by Scott Malone, Barbara Goldberg, Jeffrey Benkoe, Maureen Bavdek and Xavier Briand)