A pileup involving dozens of vehicles on a Pennsylvania interstate that killed three people and sent dozens to hospitals appears to have been related to a passing snow squall, authorities said Saturday.

Trooper Justin Summa said three fatalities had been confirmed following the 9:45 a.m. Saturday crash which involved at least 50 commercial and private vehicles. Police said more than 40 people were transported to several hospitals following the crash in Interstate 78 in Bethel Township.

The pileup left tractor-trailers, box trucks and cars tangled together across three traffic lanes and into the snow-covered median about 120 kilometres northwest of Philadelphia.

Megan Manlove of Penn State Hershey Medical Center said 10 patients had been brought in from the crash, three in critical condition, three with moderate to severe injuries and four with minor injuries.

Trooper Adam Reed said investigators believe that "passing snow squalls played a role in causing the crash."

PennLive.com reported that some witnesses reported sudden whiteout conditions on the interstate before the crash.

"It just turned real white," Raul Jardine of Allentown said, adding that all he could see were the brake lights of the car in front of him, so he slowed down and was hit from behind.

Interstate Pileup

Emergency personnel work at the site of a pileup of more than 50 vehicles near Fredericksburg, Pa., Saturday. (Daniel Zampogna/PennLive.com via Associated Press)

Nearby resident James Steffy told WHP-TV that the crash "sounded like two bombs went off."

"We thought it was thunderclouds, and my wife ran up over the hill and saw the accident," he said.

Police said more than 70 people were taken to a warming shelter operated by the American Red Cross at a firehouse in the area.

"We're keeping them warm, keeping them fed and hopefully going to provide them with some rental cars," Summa said.

Interstate Pileup

Emergency personnel work at the crash near Fredericksburg, Pa., Saturday. (Daniel Zampogna/PennLive.com via Associated Press)

The Penn State-Lehigh Valley men's basketball team was heading to a game in New Kensington when the team's chartered bus was hit by a tractor-trailer, the university said. Officials said there were no serious injuries to anyone and the students were "on a warm, dry bus" but were being taken to a hospital as a precaution.

Pennsylvania Emergency Management Agency spokesman Cory Angell said an emergency operation center was activated and a special response team was at Fort Indiantown Gap to deliver stockpiled supplies such as food and water if they are needed.

Angell said drivers were being urged to use caution due to extremely cold temperatures and blowing snow making roads hazardous even though they have been plowed.

Interstate Pileup

Emergency personnel carry an injured person from the crash. (Daniel Zampogna/PennLive.com via Associated Press)

"You could be driving down the interstate and all of a sudden conditions change because the winds are drifting the snow," he said.

Police said the interstate would remain closed until at least midnight, and people wishing to recover their cars should call the state police in Lebanon County after 6 a.m. Sunday.

The crash comes amid dangerous weather conditions that are gripping the northeastern U.S. as well as parts of Central and Eastern Canada.

'Life-threatening' cold

In some areas of the northeastern U.S. on Saturday, temperatures in some areas were set to fall below about -18 C, with Boston facing its coldest Valentine's Day in almost four decades.

Officials warned people to stay indoors away from what the National Weather Service described as "life-threatening" cold.

Wind chill advisories were in effect over parts of nine states extending from northern Pennsylvania to western Maine, with forecasters expecting gusts up to 70 km/h.

"Wind chills will be getting colder and colder as the day goes on," said Alan Dunham, a meteorologist with the National Weather Service in Taunton, Mass.

The temperature in Boston was expected to drop to -22 C overnight, but feel as cold as -35 C with the wind chill. That would be below the record low of -19 C set in 1979.

New York City was bracing for its coldest night in 20 years. Mayor Bill de Blasio said officials had put on extra staff to help respond to residents who had lost heat.

"It's so important to take this seriously, to stay indoors to the maximum extent possible, go out for as little time as possible," de Blasio told reporters.

Interstate Pileup

A crushed vehicle remains at the scene. (Daniel Zampogna/PennLive.com via Associated Press)

At Boston's Pine Street Inn 485-bed homeless shelter, workers were finding cots, mats and even chairs to accommodate the roughly 600 people they were expecting tonight, said spokeswoman Barbara Trevisan.

"No one will be turned out for lack of space," Trevisan said.

In Boston, some were hurrying through their mornings to get outdoor chores done before the worst cold set in.

"Right now I'm going to drink a coffee" to stay warm, said Carmen Pichente, 40, en route to her job at a Boston restaurant. "Tomorrow, I'm going to stay at home all day."

Others brushed it off as part of life in New England.

"It's nothing. I lived in Boston all my life," said Eddie Brown, 51, a delivery truck driver out on his rounds. Asked why he wasn't wearing a coat, Brown replied, "I got long underwear on."

With files from Reuters