Passers-by check out an uprooted tree near Lehigh Valley Monday. Hurricane Sandy soaked Philadelphia and its suburbs, but major interstates around Philadelphia have reopened. Many government offices, courts and schools were to remain closed at least through today.

PHILADELPHIA — A one-two punch of rain and high wind from a monster hybrid storm that started out as a hurricane battered Pennsylvania, leaving more than a million people without power as officials prepared to assess the damage today.

The storm soaked Philadelphia and its suburbs Monday night, but continued to churn across Pennsylvania with lashing winds and rain projected for the flood-prone state.

Major interstates around Philadelphia have reopened although some speed and vehicle restrictions remained in place across the state. Additional road closures were likely in the day ahead, as the center of the storm was forecast to hit Harrisburg before turning north toward State College.

“We ask everybody to stay inside and stay off the roads, if possible,” said Gov. Tom Corbett, who warned residents the state would not escape with just a glancing blow.

Corbett set up shop inside the Pennsylvania Emergency Management Agency headquarters outside Harrisburg, where top aides and Cabinet members were providing running updates and helping make spot decisions as events unfold. He activated 1,600 members of the National Guard, making them ready for deployment to trouble spots.

“This is going to be an event that for a period of time is going to alter the way we do things,” Corbett said.

The severity of the storm in Pennsylvania expressed itself during the day Monday through a set of increasingly worrisome numbers, from the hundreds of people who fled their homes in the southeastern part of the state to the power outages affecting more than 1.2 million customers by early today.

Bucks County was hit hard with more than 200,000 customers without power between two utility companies.

PECO reported 585,000 without power in Philadelphia and nearby counties, a total which would fluctuate as residents awoke to find their service out.

“This will still be multiple days,” PECO spokesman Fred Maher said this morning. “We’ll be able to get a lot of folks back up pretty quickly, but it’ll take us several days to get everybody back to power.”

The storm snapped trees in and around Philadelphia. Caution tape blocked both streets at one South Philadelphia intersection where splintered trees had landed on top of vehicles.

Downed trees, power lines and flooding forced a significant number of road closures across the eastern part of the state. PennDOT reopened Interstates 95 and 676 in the city and previously closed stretches of I-76 and 476 this morning but reported much work still needed to be done.

High winds were so bad at one point PennDOT pulled its crews off the roads for a time for safety reasons, spokesman Charles Metzger said this morning.

“As many trees as we’re going after, we had more trees coming around our guys,” he said.

The greatest risk of flooding was in counties along the state’s southern border, Corbett said: Chester, Lancaster, York and Adams. While officials were cautiously optimistic about the Susquehanna River, flooding in low-lying areas and for some smaller creeks and streams was considered a certainty. About a third of the state was at risk for moderate to flooding, and 23 counties set up emergency operations centers.

The National Weather Service issued small stream and urban flood warnings into this morning for much of the state. The Schuylkill River and Perkiomen Creek were each expected to reach flood stage in the Philadelphia suburbs, but forecasters expected it to remain below its banks in the city.

Rain and gusting winds up to 45 mph were still possible as the weakening storm moved across the state, the National Weather Service said.

Government offices, many courts and countless schools were shuttered on Monday and planned to remain closed at least through today. US Airways canceled all flights today out of Philadelphia International Airport and the city’s transit system was preparing to assess damage before making a decision on restarting service.

The Red Cross set up 58 evacuation centers that could shelter 31,000 people. Hundreds of people were evacuated in the Philadelphia suburbs of Bensalem Township and Darby Borough, where officials feared overnight floods.

At least three deaths were attributed to the storm. They included an elderly Lancaster County man who fell on Sunday from a tree he was trimming in advance of the storm.