Road conditions deteriorated Saturday across the central United States as a winter storm brought a mix of snow, ice and plunging temperatures, with forecasts calling for the dreaded combo to spread eastward toward Washington, D.C. in the coming days.

The polar vortex of ultra-cold air usually stays penned up around the North Pole, spinning like a top. But sometimes it escapes or stretches down to the United States, Europe or Asia — and that’s when large numbers of people experience intense doses of cold.

Snow and Ice in the Forecast

By Sunday morning, widespread heavy snow blanketed an area from central Kansas to Indiana, especially along and north of Interstate 70. Part of the interstate was closed in central Kansas by Saturday afternoon. Total snow and sleet accumulations for parts of Kansas and northern Missouri were predicted to be as high as 14 inches.

The storm is forecast to move then into the Ohio Valley, with severe travel disruptions expected. It will reach the Mid-Atlantic states on Sunday into Monday, with a hard freeze even expected as far south as Florida.

Severe thunderstorms, with the possibility of tornadoes and hail, were also possible ahead of the storm system’s cold front as it crosses the Lower Mississippi Valley, the National Weather Service warned.

Parts of upstate New York saw 3 feet or more of snow from a lake effect event expected to last until late Sunday afternoon.

Car Wrecks Start as Storm Hits

A fire truck, several tractor-trailers and passenger vehicles overturned west of Salina, Kansas. Rigs also jackknifed and went into ditches, state Highway Patrol Trooper Ben Gardner said. He posted a video showing his boots sliding across the highway blacktop like an ice-skating rink.

“We are in it now,” Mr. Gardner said as he drove to the scene of an accident. Online, he begged for prayers and warned that some roadways were nearly impassable.

Freezing rain in Wichita, Kansas, sent authorities to multiple crashes in the morning, and police urged drivers to stay home if possible and watch out for emergency vehicles.

Governors in neighboring Missouri and nearby Arkansas declared states of emergency. Whiteout conditions threatened to make driving dangerous to impossible, forecasters warned, and heighten the risk of becoming stranded.

“Please stay off the roads. Crews are seeing too many vehicles out and sliding off,” Missouri’s transportation department said on the social platform X.

Air Travel Also Snarled

The Kansas City International Airport temporarily halted flight operations Saturday afternoon due to ice. Dozens of flights were delayed, including a charter jet transporting the Kansas City Chiefs, before the runways reopened. “Work will continue overnight to keep the airfield clear,” the city’s mayor, Quinton Lucas, said in a message on X.

Stores in Wichita were filled with shoppers stocking up on groceries in advance of the storm, and warming centers opened in churches and libraries.

Several businesses closed across the Kansas City area, and the school district in suburban Independence, Missouri, said it might need to cancel classes for one or more days.

In Columbus, Ohio, crews treated major roadways with anti-icing liquids.

“It will be a major headache,” said a senior meteorologist with AccuWeather, Tom Kines. “The storm not only has the snow threat to it but the ice threat.”

Power outages could be significant particularly south of the Kansas City area, Mr.. Kines said.

Storm Moving East

Starting Monday the eastern two-thirds of the country will experience dangerous, bone-chilling cold and wind chills, forecasters said. Temperatures could be 12 to 25 degrees below normal as the polar vortex stretches down from the high Arctic.

In Chicago on Saturday, temperatures hovered in the teens and around zero in Minneapolis, while dropping to 14 below in International Falls, Minnesota, on the Canadian border.

Virginia’s governor, Glenn Youngkin, declared a state of emergency Friday evening ahead of the storm and encouraged residents to vote early on Saturday ahead of the state’s special elections Tuesday in a statement on X.

Similar declarations were issued in Kansas, Kentucky, Maryland and multiple cities in central Illinois.

“This is the real deal,” meteorologist John Gordon said at a press conference in Louisville, Kentucky. “Are the weather people blowing this out of proportion? No.”

Officials in Annapolis asked residents to remove vehicles from emergency snow routes. The historic state capital near the Chesapeake Bay also announced plans to open several garages Sunday for free parking.

The National Weather Service predicted 8 to 12 inches of snow for the Annapolis area, with temperatures remaining below freezing throughout the weekend.

In Baltimore, an extreme weather alert was issued instructing agencies to provide shelter and assistance for those in need. City officials said wind chills dipped to 13 degrees overnight Saturday and remain in the teens through Tuesday.