Snow and ice blanketed major roads across Kansas, western Nebraska and parts of Indiana, where the state’s National Guard was activated to help stranded motorists. At least 8 inches (20 centimeters) of snow was expected, along with gusting winds up to 45 mph (72 kph).

The National Weather Service issued winter storm warnings from Kansas and Missouri all the way to New Jersey.

“For locations in this region that receive the highest snow totals, it may be the heaviest snowfall in at least a decade,” the weather service said.

Gary Wright wore a parka as he and his husband chipped away at thick ice coating his SUV in a slippery apartment parking lot in Missouri. Wright said he will work remotely Monday, but wanted to scrape off his vehicle as an excuse to spend a little time in the snow. He also is seeking boots for their two older dogs that “won’t budge at all” when their paws hit the cold ground.

The polar vortex of ultra-cold air usually spins around the North Pole. People in the U.S., Europe and Asia experience its intense cold when the vortex escapes and plunges southward.

Studies show a fast-warming Arctic is partly to blame for the increasing frequency of the polar vortex extending its icy grip.

Classes canceled

School closings are expected to be widespread Monday. Districts in Indiana, Virginia and Kentucky began announcing cancellations and delays on Sunday afternoon. Kentucky’s Jefferson County Public Schools canceled classes, extracurricular activities and athletics for its nearly 100,000 students.

Classes also have been cancelled in Maryland, where Gov. Wes Moore declared a state of emergency Sunday and announced the state government would be closed Monday.

“Keeping Marylanders safe is our top priority. Please stay off the roads during this storm. Prepare your home and family and charge your communications devices in case you lose power,” Moore said in a statement.

Car wrecks proliferate as storm hits

Over the weekend, at least 600 motorists were stranded in Missouri, authorities said. Hundreds of car accidents were reported in Virginia, Indiana, Kansas and Kentucky, where a state trooper was treated for non-life-threatening injuries after his patrol car was hit.

Kentucky Gov. Andy Beshear, who declared a state emergency, said government buildings would be closed Monday.

“We see far too many wrecks out there for people that do not have to be on the roads, so I want to ask: Stay inside,” Beshear said.

Virginia State Police reported at least 135 crashes as the storm entered the state Sunday. In Charleston, West Virginia, where several inches (centimeters) of snow had fallen by Sunday night, authorities urged motorists to stay home.

Snow and ice in the forecast

In Indiana, snow fully covered portions of Interstate 64, Interstate 69 and U.S. Route 41, prompting Indiana State Police to plead with motorists to stay off the roads as plows worked to keep up.

“It’s snowing so hard, the snow plows go through and then within a half hour the roadways are completely covered again,” Sgt. Todd Ringle said.

Roughly 10 inches (25 centimeters) of snow fell in Kansas, with eventual totals predicted to top 14 inches (36 centimeters) for parts of that state and northern Missouri.

In Kentucky, Louisville recorded 7.7 inches (19.5 centimeters) of snow on Sunday, a new record for the date that shattered the previous mark of 3 inches (7.6 centimeters) set in 1910.

The storm was forecast to move into the Ohio Valley and reach the Mid-Atlantic states on Monday, with a hard freeze expected as far south as Florida. Winds downed trees around the Deep South on Sunday.

Air and rail travel also snarled

The storms caused havoc for the nation’s passenger railways with more than 20 cancellations Sunday and about 40 planned Monday.

“If local authorities are telling people not to travel, it’s counterintuitive to try to run a full slate of services when people are being told to stay home,” Amtrak spokesperson Marc Magliari said.

Nearly 200 flights in and out of St. Louis Lambert International Airport were canceled, according to tracking platform FlightAware.

Temperatures plunge

Starting Monday, the eastern two-thirds of the U.S. will experience dangerous, bone-chilling cold and wind chills, forecasters said. Temperatures could be 12 to 25 degrees (7 to 14 degrees Celsius) below normal.

In Chicago, temperatures hovered Sunday in the teens (minus 7 to 10 Celsius) and dropped to 11 below (minus 11.7 Celsius) in International Falls, Minnesota, on the Canadian border.

The Northeastern states are more likely to experience several days of cold after a mostly mild start to winter, said National Weather Service meteorologist Jon Palmer in Gray, Maine.

The cold air likely will grip the eastern U.S. as far south as Georgia with parts of the East Coast experiencing single-digit lows, Palmer said.