At least two people were killed and multiple people were injured in a multi-vehicle pileup involving dozens of cars during a winter storm Wednesday in Central Pennsylvania.

Pennsylvania State Police spokesman Cpl. Brent Miller said the incident happened around 3:05 p.m. on Interstate 80 westbound near mile marker 183 in Clinton County.

"It involved 30 to 60 vehicles with multiple injuries and right now there are two fatalities," Miller told weather.com in a phone interview at around 7:30 p.m. EST.

Rescuers were still on the scene and Miller said the number of casualties could rise.

"They are still going through the wreckage as we speak," he said.

(MORE: The Latest Forecast for Winter Storm Gail)

Miller said it was snowing at the time but the cause of the crash was under investigation.

Winter Storm Gail was dumping snow on the region Wednesday afternoon and into the evening.

"A squall of snow was producing heavy, wet snowfall as it moved northward through Pennsylvania, likely contributing to visibilities of less than one-half mile and slick roads at times," weather.com digital meteorologist Jonathan Belles said.

Meanwhile, police in Virginia and Maryland responded to hundreds of crashes while cities across the mid-Atlantic and Northeast, including New York, Boston and Philadelphia, salted roads, pre-positioned plows and asked residents to avoid travel as the storm moved in.

As of the late afternoon, Virginia State Police had responded to about 200 crashes and 125 disabled or stuck vehicles along Interstate 81 and across Northern Virginia.

About 36,000 homes and businesses were without power across the state as of about 7:55 p.m. EST, according to poweroutage.us.

Maryland State Police responded to 489 calls for service, including 161 crashes and 60 unattended or disabled vehicles between 9 a.m. and 3 p.m.

The system, named Winter Storm Gail by The Weather Channel, is expected to bring heavy snow, strong winds and possible coastal flooding into Thursday. Winds could gust as high as 50 mph in some areas.

"If you absolutely don't have to travel tonight or tomorrow, it would be great if you could just stay put and let the road crews do the work that they need to do," Massachusetts Gov. Charlie Baker said in a Wednesday afternoon news conference.

"The last thing we all need to deal with right now, in the midst of everything else that's going on, are car accidents and other collisions as a result of what will be fairly treacherous driving conditions."

Baker pointed out that traffic is lighter than usual due to a large number of people working from home. Massachusetts also has a stay-at-home advisory nightly from 10 p.m. to 5 a.m. due to coronavirus restrictions.

He said 3,800 pieces of snow-clearing equipment would be deployed for operations on about 15,000 miles of highways.

Officials throughout the affected regions declared states of emergency and echoed Baker's plea to stay at home.

The mayor urged residents to take mass transit or work from home, if possible.

New Jersey Gov. Phil Murphy declared a state of emergency, effective at 2 p.m. Wednesday. The state also issued commercial vehicle travel restrictions on portions of several interstates, including I-78, I-80 and I-280. Vehicles under the restrictions include tractor-trailers, passenger vehicles pulling trailers, recreational vehicles and motorcycles.

The speed limit was lowered to 35 mph on the Delaware Memorial Bridge, which carries Interstate 295 across the river from New Jersey to Delaware.

(MORE: Winter Storm Gail Won't Stop COVID-19 Vaccine Distribution, State, Federal Officials Say)

Pennsylvania Gov. Tom Wolf also issued a disaster emergency proclamation for most of his state.

“Commonwealth agencies have been watching this storm for several days, and we are ready to provide whatever support is needed to keep our citizens safe during this potentially dangerous storm,” Wolf said in a news release. “We encourage you to prepare now to keep your loved ones safe, and also avoid any unnecessary travel.”

Crews and equipment were ramped up to keep roadways clear.

"One-hundred pieces of equipment are expected to be mobilized during the beginning of the event," Philadelphia Streets Commissioner Carlton Williams said, according to WPVI-TV. "We're preparing for a full deployment of additional crews and equipment contingent upon additional snow accumulation throughout the entire event."

More than 300 snow plows were deployed overnight in Washington D.C. to apply salt to highways, streets, ramps, bridges and elevated roadways.

Crews in Charlottesville, Virginia, were applying 20,000 gallons of brine solution to help keep roads clear, WWBT-TV reported. Similar operations were happening around the state, according to the state Department of Transportation.

In New York City, de Blasio announced that schools would transition to virtual learning on Thursday.

Philadelphia schools, already in virtual learning, will continue with classes, the city said in a news release.

(WATCH: Why the Weight of Gail's Snow Might Matter More Than the Amount)

Amtrak modified or canceled several train routes through Friday.

Winter Storm Gail is likely to impact air travel, too. Delta, Southwest, United and American Airlines are waiving change fees for flights that might be affected. Airport officials advised travelers to monitor flight status closely.

Because power outages are possible, officials were also reminding people to practice care when using generators or other equipment such as gas grills.

“Our concern is that carbon monoxide is a leading cause of accidental deaths in the U.S.,” Pennsylvania State Fire Commissioner Bruce Trego said, according to WATM-TV.

Generators should be placed at least 10 feet from buildings and gas grills should never be used indoors. Trego also reminded residents not to warm up their car inside a garage, even with the garage doors open.

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