At one end of the Mississippi River is the Big Easy, and at the other is the Big Freezy.

There's little chance Wednesday that high temperatures in vast swaths of Minnesota will shed the minus sign, and high winds have prompted the National Weather Service (NWS) to warn of "dangerously cold windchills."

The weather service cautions that the temperature and wind combination "will result in frostbite and lead to hypothermia, if precautions are not taken."

The word from Regions Hospital in St. Paul is that it appears people are being smart about moving about in the cold. As of 9:30 a.m., spokeswoman Kelli Trask said, the emergency room has not seen any cases of frostbite or hypothermia in the past 24 hours.

"It's like people are not going out," Trask said. "At 10, 20 degrees, they seem to be more careless."

In Minneapolis, Hennepin County Medical Center had a more sobering report, saying two people were brought in Tuesday night to the emergency room for exposure to the cold but did not require hospitalization.

In the past seven days, hospital spokesman Tom Hayes said, 18 people have been seen in the emergency room for weather-related problems. Twelve were treated for exposure, and another six had frostbite. Two of those required hospitalization, Hayes said.

Tow trucks have been busy clearing stalls from metro area roads Wednesday morning. The frigid weather also is keeping phones at AAA Minnesota-Iowa ringing. As of 8 a.m., the motoring club had received 476 calls for service. That is more than double the average of 230 calls on a typical day, said spokeswoman Gail Weinholzer.

"We are busy in the morning, we see an ebb in the afternoon and then another spike around 5 p.m., when people want to go home and their car won't start," she said.

Dead batteries are the No. 1 reason motorists call for help. But drivers who start their cars to warm them up and accidentally lock the keys inside are the second most common type of SOS callers, Weinholzer said.

David Bodin-Huber, manager of the Firestone Tire and Auto Center in Bloomington, said he's seen an uptick in business since the cold snap hit.

"We've seen everything from cars not starting, leaking antifreeze, windshield wipers that don't work and tires not gripping. Pretty much everything," he said.

For the Twin Cities area, the NWS is projecting a real-temperature high of just short of 0, with windchill readings ranging from 25 to 35 below. The actual overnight low is forecast to bottom out at 10 below.

A warm-up — and that's a relative term — comes Thursday, with high of 17 above expected for the metro. By the way, the first day of winter doesn't arrive until the end of next week.

Blaine was claiming Wednesday's lows in the Twin Cities area, at minus 9 as of 9 a.m. Crystal and Lakeville were close behind at 8 below. By 1 p.m., Lakeville was the metro's chilly spot at minus 2.

The Salvation Army, which offers shelter for the homeless in the metro area, said the extreme cold means people seeking warmth want to stay inside throughout the day, so "our biggest challenge … is finding space and supervision staff to allow people inside all day long," said spokeswoman Annette Bauer. "Typically, in good weather, they need to leave by 7:30 a.m. and are back in for the night around 7:30 p.m."

In conditions like Wednesday's, "we keep the chapel open all day for people to stay inside out of the elements. At times, that room will get very full, and we need to make use of hallways with chairs."

Bauer added that the subzero readings also make it challenging for the Salvation Army to keep its many red kettles staffed during its signature fundraising effort.

"We just sent something out to our volunteers and posted on our website to search for those hardy Minnesotans," she said. It calls on those already with cold-weather gear — deer hunters, snowmobilers, skiers and hockey players — to grab a handbell and staff a kettle.

"Show Old Man Winter your warm heart is stronger than his cold weather," the pitch implores.

Beyond the metro area, other 9 a.m. readings around the state included: Fosston in the northwest at 26 below, Park Rapids at minus 24, International Falls at 22 below, Ely and Fergus Falls at minus 20, Cloquet and Pipestone at minus 17, New Ulm at 13 below, and Austin and Rochester at minus 6.

Even by the time the sun was at its peak, temps around the state at 1 p.m. included minus 13 in Thief River Falls, 9 below in Fergus Falls and minus 4 as far south as New Ulm. The warm spot? Winona at 5 above.

Meanwhile, Wednesday's high in New Orleans, where the Mississippi meets the Gulf of Mexico, is forecast to be about 60 under partly cloudy skies. No word on the windchill.

paul.walsh@startribune.com • 612-673-4482 harlow@startribune.com • 612-673-7768