MINNEAPOLIS >> A monster winter storm took aim at the Upper Midwest today, threatening to bring blizzard conditions, bitterly cold temperatures and 2 feet of snow in a three-day onslaught that could affect more than 40 million Americans.

The storm began around midday and was to continue through Thursday morning in parts of the Dakotas, Nebraska, Minnesota, Iowa and Wisconsin, with winds gusting as high as 50 mph (80 kph) and wind chills tumbling as low as minus 50 degrees (minus 46 Celsius) in some places.

The snowfall could be historic, even in a region accustomed to heavy snow. As much as 25 inches may pile up, with the heaviest amounts falling across east-central Minnesota and west-central Wisconsin, the National Weather Service said.

The Minneapolis-St. Paul area could see 2 feet of snow or more for the first since in over 30 years.

Some families scrambled to get shopping done before the weather closed in. At a Costco in the Minneapolis suburb of St. Louis Park, Molly Schirmer stocked up on heat-and-serve dinners and Mexican Coca-Colas, knowing that she and her two teenagers might get stuck at home.

“The schools are already preparing to go online, so the kids will probably be home doing online school,” Schirmer said of her 13- and 15-year-olds.

At another Costco in suburban Eagan, Larry and Sue Lick bought toilet paper, kitchen essentials and coffee ahead of the storm. They also rescheduled medical appointments and a family gathering, just to stay off the roads.

“It’s not so much our driving, but you’ve got to worry about everybody else driving, with so many accidents caused by people that don’t know the winter driving,” Larry Lick said.

The weather service said the blizzard will actually involve two rounds. For the Minneapolis-St. Paul area, the first blast arrives Wednesday afternoon with up to 7 inches of snow. Round 2 starting later Wednesday and extending into Thursday is the real whopper, “with an additional 10 to 20 inches expected.”

Weather service meteorologist Frank Pereira said the system was expected to affect about 43 million Americans.

Forecasters warned of life-threatening conditions.

Temperatures could plunge to minus 15 to minus 20 degrees on Thursday (minus 26 to minus 29 Celsius) and minus 25 degrees (minus 32 Celsius) Friday in Grand Forks, North Dakota, meteorologist Nathan Rick said. Wind chills of 50 degrees below zero were possible.

Wind gusts of 35 mph (56 kph) will be common in western and central Minnesota, with some blowing even stronger. That will result in “significant blowing and drifting snow with whiteout conditions in open areas,” the weather service said.

According to the weather service, the biggest snow event on record in the Twin Cities was 28.4 inches from Oct. 31 through Nov. 3, 1991 — known as the Halloween Blizzard. The second-largest was 21.1 inches of snow from Nov. 29 through Dec. 1, 1985. The Twin Cities got 20 inches of snow on Jan. 22 and Jan. 23, 1982.

Hours before the snow was to start, the storm was already having an impact. Minnesota state lawmakers canceled all committee hearings scheduled for Wednesday and Thursday as well as the Thursday floor sessions. Since they don’t normally meet on Friday, legislators won’t reconvene until Monday.

Hardware store owners said customers were generally taking the forecast in stride.

At C&S Supply, an employee-owned hardware store in Mankato, manager Corey Kapaun said demand was high for salt and grit, but not for shovels, snow blowers or other equipment. He attributed that to the fact that winter is two-thirds over.

Kapaun said he’s sold 130 to 140 snow blowers and around 1,000 shovels this winter, when Mankato has seen more than 3 feet of snow.

“I think people are either prepared or they’re not,” Kapaun said. “It’s usually the first snowfall of the year that gets a lot of attention. With a storm like this, I expected a little bit more, but we’ve already had a big year of snow already.”

In Sioux Falls, Dallas VandenBos has owned Robson True Value hardware store for 48 years. His customers are used to the snow, but don’t necessarily trust the forecast.

He recalled a storm in early January that was supposed to drop 3 or 4 inches of snow. The total was much higher — 18 inches.

Sales of snow-related items haven’t really picked up, but VandenBos has a backlog of snow blowers to repair. Those bringing them in Tuesday were out of luck — they won’t be ready for a week.

“They’re not going to get them in time for this snow,” VandenBos said.

Forecasters at AccuWeather said the same storm system could result in icing across a 1,300-mile (2,092 -kilometer) band from near Omaha, Nebraska, to New Hampshire on Wednesday and Thursday, creating potential travel hazards in or near cities such as Milwaukee, Detroit, Chicago and Boston.

Portions of northern Illinois, southern Michigan and southern New York state could get up to half an inch of ice, which could topple power lines and cause outages, AccuWeather said.

In California, significant snow was possible in the foothills and mountains near Los Angeles, with several inches predicted even for elevations as low as 1,000 feet, the weather service said.

Nearly the state’s entire population “will be able to see snow from some vantage point later this week if they look in the right direction,” UCLA climate scientist Daniel Swain wrote on Twitter.

Potentially damaging 50 mph (80 kph) winds were predicted along the central coast, and gusts of 70 mph (113 kph) were possible in the mountains.

As the northern U.S. deals with a winter blast, record warmth was expected later in the week in the mid-Atlantic and Southeast — 30 degrees to 40 degrees above normal in some places. Record highs were likely from Baltimore to New Orleans and in much of Florida, Pereira said.

Washington, D.C., could hit 80 degrees on Thursday, which would top the record of 78 degrees set in 1874.