ANNAPOLIS, Md. — A major winter blast of snow, ice, wind and plunging temperatures in the U.S. stirred dangerous travel conditions from central and southern states all the way to the East Coast early Monday, prompting schools and government offices in several states to close.

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. Nearly 300,000 customers were without power early Monday across Kentucky, Indiana, Virginia, West Virginia, Illinois and Missouri, according to electric utility tracking website PowerOutage.us.

The National Weather Service issued winter storm warnings for Kansas and Missouri, where blizzard conditions brought wind gusts of up to 45 mph (72 kph). The warnings extended to New Jersey for Monday and into early Tuesday.

“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 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.

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.

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.

Classes Canceled

School closings are expected to be widespread Monday. Districts in Indiana, Virginia, Kentucky, Missouri and Kansas 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 injuries that were not life-threatening 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.

Road crews remained on duty overnight and were making headway Monday morning, the state Transportation Cabinet said in a social media post. But the agency warned that ice was an issue on roads, especially mid-state and northward where there was more packed snow.

Virginia State Police responded to at least 230 crashes statewide, with more than 20 injuries, between 4 p.m. Sunday until 4 a.m. Monday. There was one fatal crash, but it wasn’t clear if it was storm-related, police said. 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.

Topeka, Kansas, reported 14.5 inches (36.8 centimeters) about 8 p.m. Sunday, according to the weather service.

Kansas City International Airport received a record snowfall of 11 inches (28 centimeters) on Sunday, breaking the previous record for the day of 10.1 inches (26 centimeters) set in 1962, according to the weather service’s office in Kansas City, 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.

Severe travel delays were expected to continue Monday as the storm moved into the Mid-Atlantic, where another 6 inches to 12 inches ( 15 to 30 centimeters) of snow were expected, the weather service’s Weather Prediction Center warned. Dangerously cold temperatures were expected to follow, with nighttime lows falling into the single digits through the middle of the week across the Central Plains and into the Mississippi and Ohio Valley. In the Mid-Atlantic, lows were expected to fall into the teens with daytime highs near freezing.

A hard freeze was 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 more than 40 planned Monday and two already planned on Tuesday.

“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.

More than 1,400 flights were canceled and another 740 delayed nationwide on Monday morning, according to tracking platform FlightAware. Ronald Reagan Washington National Airport was reporting about 46% of arrivals and 59% of departures canceled.