ST. LOUIS >> A dangerous winter storm swept the northern U.S. on Friday, with blinding snow in some places, freezing rain in others, and bitter cold temperatures and whipping winds across several states.

The massive storm continues a week of strong winter weather for much of the U.S. that has led to deadly avalanches and treacherous ice-covered roads. On Friday, a man was believed dead in an avalanche in the Idaho backcountry. A Wisconsin man died while snow-blowing his driveway.

Political leaders in Illinois implored Texas Gov. Greg Abbot to stop sending migrants to Chicago, which is on the verge of dangerous weather. Abbott refused.

Heavy snow and strong winds made driving virtually impossible in parts of Iowa, so much so that Republican presidential hopefuls called off campaign events. “Black ice” from freezing rain caused wrecks and brought Kansas City, Missouri, to a standstill. Flight cancellations were common, including more than 1,000 at Chicago’s airports.

In Idaho, two men were rescued after being caught in the avalanche Thursday afternoon near the Montana border, but a third man was missing and presumed dead. The U.S. Air Force assisted in the search and rescue. Authorities weren’t sure what the men were doing in the area that had been under an avalanche danger warning for several days.

The Idaho avalanche came a day after the first U.S. avalanche death of the season was reported in California on Wednesday.

The Milwaukee County Medical Examiner’s office said Friday afternoon that it was investigating the death of a 69-year-old man who became unresponsive while snow-blowing his driveway in Franklin, a Milwaukee suburb. No further information was released.

Republican candidates campaigning ahead of Monday’s Iowa caucuses were contending with a blizzard warning covering most of the state. Nikki Haley’s campaign canceled three Friday events and said it would be hosting “telephone town halls.” Ron DeSantis’ campaign postponed events in Marshalltown and Clear Lake.

The Iowa State Patrol posted photos of an icy wreck. “Please, don’t put yourself or others in danger,” the agency wrote. “The road conditions are extremely dangerous!”

Blizzard warnings were issued in some places, including southwestern Minnesota and the Green Bay area of Wisconsin. Forecasts for the Milwaukee area predicted heavy snow stretching into Saturday morning with wind gusts up to 40 mph (64 kph).

The cold was the bigger concern in the Dakotas. It was 11 degrees below zero F (minus 24 C) in Bismarck, North Dakota, on Friday morning, and forecasters warned the weekend will get even worse. It could reach 20 below F (minus 29 C) by early Sunday.

Chicago is expecting several inches of snow through the weekend, with wind chills well below zero. Advocates worried for the growing population of migrants sent up from the U.S.-Mexico border — more than 26,000 have arrived since last year. By Friday, dozens were staying in eight parked “warming buses” to avoid sleeping outside while they await space in city-run shelters.

Angelo Travieso, a Venezuelan bused up from Texas, wore a light jacket and sandals with socks after sleeping on one of the buses.

“I slept sitting because there is almost no space left,” he said. “The buses are also small and you practically have to stay inside because of the heating, because it is deadly cold outside.”

Mayor Brandon Johnson said the city will suspend plans to enforce a 60-day cap on shelter stays for asylum seekers through at least Jan. 22 because of the cold snap.

Meanwhile, Illinois Gov. J.B. Pritzker released a letter pleading with Abbott.

“As we grapple with the existing challenges of your ongoing manufactured crisis, the next few days are a threat to the families and children you are sending here,” Pritzker wrote. “I am pleading with you to at least pause these transports to save lives.”

In a replying statement, Abbot refused to stop what he called “voluntary” trips “until President Biden steps up and does his job to secure the border.”

Temperatures were below zero Fahrenheit across Montana on Friday morning with wind chills as low as minus 57 F (minus 49 C) in places along the eastern edge of the Rocky Mountains and in the central part of the state.

At the Double Cross Cattle Company, a ranch near Roberts, Montana, Tyson Ropp used an axe to chop through inches of ice covering a stock tank so that his bulls could drink water. He used a feed truck to spread extra hay for his cows, a process he planned to repeat later Friday.

Temperatures were expected to drop overnight to minus 28 F (minus 33 C), so Ropp said he’d spread straw on the ground, somewhere out of the wind, for the cattle to rest and stay dry.

“It’s going to get pretty chilly tonight,” he said, “We’ve got a couple hidey holes they can get into and bed down and hunker down together and stay warm.”

Ropp shrugged off the cold.

“It’s just Montana,” he said.

Near-record cold in Kansas City will make for a frigid NFL playoff game Saturday night, when the Chiefs host Miami. The game-time temperature could be below zero. Fans will be allowed to bring in blankets for their laps and cardboard to put under their feet to stay warm. The University of Kansas Health System set up a clinic and several first aid stations at Arrowhead Stadium.

“We could really get busy,” emergency medicine physician Dr. Dennis Allin said at a briefing on Friday.

Another playoff game will face winter’s wrath on Sunday. Fans in Buffalo will contend with up to a foot of snow and fierce winds as the Bills host Pittsburgh.

Other areas of the Northeast had flooding concerns. Emergency responders helped evacuate some residents from their homes in Paterson, New Jersey, early Friday as the Passaic River started overflowing its banks. The new storm, combined with one earlier in the week, created flooding worries in Maine and New Hampshire, too.

The South wasn’t immune. Severe storms with winds reaching 70 mph (113 kph) stretched across Mississippi.

Arctic air is expected to arrive in the South by this weekend. The Mississippi Emergency Management Agency urged residents to prepare for ice, frigid temperatures and possible prolonged power outages. Louisiana Gov. Jeff Landry declared a state of emergency Friday in anticipation of temperatures plunging over the weekend, with a chance of sleet and snow early next week.

Abbott on Friday encouraged Texans to get ready, too. Temperatures will reach only into the 30s Sunday through Tuesday, with ice in the forecast for Monday. But Abbott said the cold and ice “will not be anything close to what we experienced during winter storm Uri.” That storm in February 2021 caused over 3 million Texans to lose power.

Volunteers and city leaders in several places were worried about the homeless.

Portland, Oregon, is more accustomed to winter rain, but snow was in the forecast. Tyrone McDougald wore a long-eared, leopard-style hat on Thursday as he sorted through racks of warm clothes at a homeless service center. He was already wearing multiple layers, but with no roof of his own, he grabbed two more coats to help him face a bitter cold snap arriving in the Northwest.

“I’m hoping that I can get in a shelter,” he said. “That would relieve a lot of the burden.”

Rush reported from Portland, Oregon. Associated Press reporters Katie Foody, Sophia Tareen and Melissa Perez Winder in Chicago; John O’Connor in Springfield, Illinois; Mathew Brown in Roberts, Montana; Gillian Flaccus in Portland, Oregon; Rick Callahan in Indianapolis; Patrick Whittle in Portland, Maine; Amy Beth Hanson in Helena, Montana; Todd Richmond in Madison, Wisconsin; Acacia Coronado in Austin, Texas; Heather Hollingsworth in Mission, Kansas; Michael Goldberg in Jackson, Mississippi; and Kevin McGill in New Orleans contributed to this report.