Updated

A tour bus carrying more than 30 passengers flipped over on an upstate highway Wednesday night and landed upside-down in a ditch, injuring several people and trapping at least one woman underneath it.

Four people were seriously injured and 36 others suffered minor injuries, a dispatcher for the Broome County Sheriff's Office said.

The accident, the latest in a string of bus crashes in the Northeast this year, occurred on Interstate 81 in a southbound lane near Whitney Point, a scenic village of about 1,000 residents. The bus, which appeared to have no markings on its sides, sat in the ditch on its roof with its wheels in the air.

First responders worked frantically to free a woman who was trapped under the bus, Whitney Point Fire Department Chief Nicholas Sculley said.

The woman, who was conscious and alert, had been partially ejected through the bus roof escape hatch, which had come open. She was lying on her back with her head under the bus, in a gap between the ground and the bus. She was rescued with no obvious external injuries other than a couple of cuts to her face, Sculley said.

"A centimeter either way," he said, "and it would have been a different outcome."

State Police Sgt. Todd Burdick told the Binghamton Press & Sun-Bulletin that the bus was coming from Niagara Falls and heading to Trenton, N.J. He said weather and speed too fast for conditions caused the accident.

"At the time, there was a severe downpour," Burdick told the paper.

Paramedics were evaluating people, many with neck and chest injuries, at the scene.

At Lourdes Hospital, in Binghamton, about 20 miles south of Whitney Point, clinical manager Barb Anderson said people from the bus were getting X-rays and tests and it was unclear how many would be admitted. There were no young children among the injured, but two patients appeared to be in their teens, she said.

The southbound side of I-81 was closed around Whitney Point because of the accident, Department of Transportation spokesman Dave Hamburg said. The cause of the accident hadn't been determined.

Tour bus industry safety has drawn heightened attention since the March 12 crash of a bus returning to New York City's Chinatown after an overnight excursion to a Connecticut casino. Fifteen people were killed when the bus flipped onto its side and struck a pole, peeling off its roof.

A passenger has said the driver fell asleep; the driver has said he was alert and well-rested. That crash is being investigated by state police and the National Transportation Safety Board.

Since that crash, New York has sidelined hundreds of buses and bus drivers in a stepped-up program to stop buses for safety evaluations. Many drivers were found to have had multiple driver's licenses with histories of violations.

Just days after that deadly crash, a luxury tour bus from New York City's Chinatown to Philadelphia crashed on the New Jersey Turnpike, one of the nation's most heavily trafficked highways, killing the driver and another person. The bus entered the grass along the center median before striking an overpass support and hitting an embankment.

Last month, a fiery crash between a tractor-trailer and a tour bus in upstate New York killed the truck driver and injured at least 30 passengers on the bus.