PHILADELPHIA — Gov. Ed Rendell declared a disaster emergency in Pennsylvania on Saturday as a winter storm brought heavy snow and gusty winds that cut off power to tens of thousands and forced road closures.

The governor's declaration allows officials to bypass bid and contract procedures to deal with the emergency. Pennsylvania National Guard forces had been deployed to help state police, Rendell said.

Disaster emergencies have been declared in Butler, Zelienople, Cranberry Township and Saxonburg.

About 17.8 inches of snow have fallen in Philadelphia, according to the National Weather Service, and totals are even higher to the west, with 28 inches in Upper Strasburg in Franklin County, 27 inches in Glen Rock in York County, 26 inches in parts of Blair and Somerset counties and 25 inches in Cambria County.

Butler County got one to two feet of snow.

In Western Pennsylvania, Allegheny Power reported nearly 120,000 customers without power and Duquesne Light had another 51,000 without power.

Allegheny County also declared a state of emergency and urged all nonessential vehicles to stay off the roads. Pittsburgh International Airport closed about 6 a.m. but expected to reopen at noon.

Several interstates were shut down overnight as stuck tractor-trailers or downed power lines blocked roads, and I-376 leading out of Pittsburgh toward Ohio remained closed Saturday. Emergency workers said secondary roads were mostly impassable.

The Pennsylvania Turnpike Commission said the toll roads remained open but had several trouble spots. Officials urged anyone planning on traveling to reconsider.

Larry Struble, a meteorologist with the National Weather Service in Pittsburgh, said the storm was on track to be the city's fourth-highest snowfall on record.