A huge swath of the U.S. was blasted with ice, snow and wind on Monday as the polar vortex that dipped south over the weekend kept much of the country east of the Rockies in its frigid grip, making many roads treacherous, forcing school closures, and causing widespread power outages and flight cancellations.

In Kentucky’s biggest city, Louisville, Hugh Ross used his shovel Monday to break hard sheets of ice as he cleared a driveway. Frozen rain fell atop several inches (centimeters) of snow that arrived Sunday, which he said “couldn’t have been worse.”

“You’ve got to break it up first,» Ross explained. «If you don’t do that, you’re wasting your time. I did a couple of layers yesterday, so I had to make sure I wasn’t in too bad of shape today.”

Ice and snow blanketed major roads in Kansas, western Nebraska and parts of Indiana, where that National Guard was activated to help stranded motorists. More than 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 into early Tuesday.

At the storied Calumet Farm in central Kentucky, the thoroughbreds were led to their stalls Sunday afternoon before freezing rain turned their pastures into a slick glaze of snow and ice.

“The ice is the worst part,” Eddie Kane, the farm manager, said Monday. “I still haven’t turned them out because it’s still a little bit too dangerous. It’s like an ice-skating rink out there in the fields.”

And in his central Missouri apartment complex’s parking lot, Gary Wright wore a parka as he and his husband chipped away at the ice coating his SUV. Wright, a 33-year-old North Carolina native, said he would work remotely on Monday but wanted to scrape off his vehicle as an excuse to spend time in the snow.

The polar vortex of ultra-cold air usually spins around the North Pole, but it sometimes escapes and plunges southward into the U.S., Europe and Asia. 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. would be dealing with bone-chilling cold and wind chills, forecasters said. Temperatures could be 12 to 25 degrees (7 to 14 degrees Celsius) below normal.

The Northeast, which has had a relatively mild start to winter, is likely to experience several days of cold, said Jon Palmer, a weather service meteorologist based in Gray, Maine.

The cold air was expected to grip the Eastern Seaboard as far south as Georgia, with temperatures dropping into the low single digits (minus 15 to minus 17 Celsius) in some coastal areas, Palmer said. Major southern cities including New Orleans and Dallas were bracing for uncharacteristically cold weather.

And Washington, D.C., received heavy snow as President-elect Donald Trump’s victory was set to be certified. Taking advantage of the rare snowstorm in the nation’s capital, revelers engaged in a snowball fight in front of the Washington Monument as flags flew at half-staff in memory of former President Jimmy Carter.

President Joe Biden was closely monitoring the severe weather and making sure the federal government would assist affected states, a White House spokesperson said.

Classes canceled

School closings were 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 were also canceled in Maryland, where Gov. Wes Moore declared a state of emergency Sunday and announced that state government offices would also be closed Monday.

Car wrecks proliferate

At least 600 motorists were stranded in Missouri over the weekend, 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,” Beshear said.

Virginia State Police responded to at least 230 crashes from 4 p.m. Sunday through 4 a.m. Monday. More than 20 people were injured in those crashes, and there was one fatal crash, but it wasn’t clear if it was storm-related, authorities said. More than 200 additional crashes took place later in the morning. In Charleston, West Virginia, where several inches (centimeters) of snow had fallen by Sunday night, authorities urged motorists to stay home.

More snow and ice in the forecast

In Indiana, snow fully covered portions of Interstate 64, Interstate 69 and U.S. Route 41, leading authorities to plead with motorists to stay off the roads.

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

Topeka, Kansas, reported 14.5 inches (nearly 37 centimeters) by about 8 p.m. Sunday, according to the weather service.

Kansas City International Airport received of 11 inches (28 centimeters) of snow 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 (nearly 20 centimeters) of snow on Sunday, shattering the date’s previous record of 3 inches (nearly 8 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 valleys.

A hard freeze was expected as far south as Florida. Winds downed trees around the Deep South on Sunday.

Air and rail travel are 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.

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

A record 8 inches (more than 20 centimeters) of snow fell Sunday at the Cincinnati/Northern Kentucky International Airport, leading to dozens of flight cancellations that lingered into Monday. A few more inches of snow was expected Monday across the Cincinnati area, where car and truck crashes Monday morning shutdown at least two major routes leading into downtown.