Minnesotans scrambled to stock up and kids got outside one last time Monday before hunkering down for a once-in-a-generation chill that's expected to send temperatures and windchills plummeting to dangerous levels.

For many schoolkids, it's an unexpected winter break. Schools closed Monday because of snow, then Tuesday and Wednesday because of the cold, sending parents in search of last-minute child care.

Temperatures are expected to dive to 30 below in the Twin Cities by Wednesday morning for the first time since 1996.

"We generally don't get a low temperature that exceeds 30 below more than once every 20 years," said Tyler Hasenstein, a meteorologist with the National Weather Service. It has only happened nine times since the 1940s.

Minneapolis and St. Paul public schools were among the dozens of schools and colleges closed through Wednesday.

Many school districts follow protocols that trigger closures when temperatures dip to 25 below or 35-below windchill, said Gary Amoroso, executive director of the Minnesota Association of School Administrators. The double closures Monday were nonetheless rare.

"I've been in this state for 18 years and this is one of the first times that we've seen that," Amoroso said.

Gov. Tim Walz asked his staff last week to determine under what circumstances the state would shutter all schools, as last happened in 2014. On Monday, he advised parents and students to watch for messages from local school districts.

"No matter how resilient the people of Minnesota may be, this weather should be taken seriously." Walz said.

'Nowhere to go'

Meanwhile, homeless outreach workers in Minneapolis have been rushing to equip people living outside with warm clothing. A number of shelters also announced they would remain open around the clock.

John Tribbett, street outreach program manager for St. Stephen's Human Services, a nonprofit which serves the homeless, said the shelter system is insufficient to house everyone who needs it.

"There's a lot of people outside that literally have nowhere to go," he said. "It's always life and death, because being on the street is always dangerous. When the weather is like it is … the risk of death is greatly exacerbated."

His team is making morning checks at known encampments to ensure people have survived the night and see if they need medical care.

"People unfortunately fairly regularly do pass away in extreme weather," Tribbett said, adding, "Every year we have many, many people that we work with experience fairly severe frostbite, and people lose fingers and limbs."

In Rochester, a man found dead outside a home early Sunday may have succumbed to bitterly cold temperatures, although authorities are awaiting autopsy results before confirming the nature of Ali Gombo's death.

The 22-year-old Rochester man was found on the back deck of his sister's house, where he had been living, according to police. Authorities said Gombo was dropped off near the house early Sunday. He did not have keys to the residence.

Evidence at the scene suggested that he went to several doors and windows of the house in an attempt to get someone's attention. He apparently went to a neighbor's house and knocked on their door as well.

A neighbor spotted the body and called police shortly after 10 a.m. Sunday. Gombo was found without his shirt on. People sometimes undress in the late stages of hypothermia.

His death is not being regarded as suspicious, police said.

Temperatures in Rochester plunged to 15 degrees below zero early Sunday, with wind speeds up to 29 mph.

Stocking up

Temperatures in the single digits were already causing trouble for some motorists on Monday. Those who called AAA Minneapolis for jump-starts and flat tires were waiting one to two hours for service, said spokeswoman Meredith Terpstra.

Cities across the metro area declared snow emergencies after 2 to 6 inches of fluffy snow fell across the metro Sunday night and into Monday morning.

The fast-moving clipper coated roads with ice and snow even though the state Department of Transportation had more than 200 trucks working to get them in shape for the morning rush.

A mood of preparation lingered around downtown Monday, including at Target, where Steve Shook was stocking up on cat food. "Normally I shop every day, but right now I'm stocking up for the week," Shook said.

"I think I'm going to stock up good and keep things at home so I don't have to go out unnecessarily in the next few days," said Victoria Rush.

Shannon Nichols of Shakopee was downtown with her daughter, fifth-grader Arianna Van Beusekom.

Nichols said that she and her four children this week plan to watch movies and work on extra-credit projects offered when Shakopee schools are closed.

Gas stations saw a bump in commuters heading home Monday who stopped to grab fuel and air up tires ahead of the cold.

Sunday night was especially busy at the Moto Mart off of Hiawatha Avenue in south Minneapolis, cashier Alyssa Wolfe said.

"Every pump had somebody on it," Wolfe said.

She said Monday was also busier than normal during rush hour as customers topped off their cars, grabbed snacks and stocked up on things like cigarettes.

"People haven't been crabby," she said. "They just want to get to home."

Teri Ferguson of Colorado Springs, came to Minneapolis for a business conference. She said she is shocked by the frigid temperatures.

"It never gets this cold in Colorado, ever," Ferguson said. "You guys do a great job of keeping us all indoors. With the skyways, everything is indoors."

Hasenstein, with the National Weather Service, said people should be wary of frostbite and becoming stranded in a vehicle.

"The main thing that we're letting people know is don't be out and about if you don't have to,"he said.

Staff writers Tim Harlow, Hannah Covington, Matt McKinney and University of Minnesota student Isabella Murray contributed to this report.