(Reuters) - The town that embraces its nickname as the “Icebox of the Nation” barely paused on Wednesday for the polar vortex that is gripping the U.S. Upper Midwest.

International Falls, Minnesota, a town of 6,000 people on the Canadian border, was among the coldest places in the United States, recording a low temperature of minus 36 Fahrenheit (minus 38 Celsius) on Wednesday with a wind chill factor of minus 55F (minus 48C), according to the National Weather Service.

That was colder than the South Pole, but still, it was “only 36 below,” Mayor Bob Anderson said.

“It’s business as usual. All the businesses are open in town,” Anderson said. Firefighters reported no unusual emergency calls.

The schools were closed but “schools are more cautious today than they used to be in the past,” said Anderson, 76, who was born and raised in International Falls.

The forecast low overnight was minus 49F (minus 45C), and even that would not be enough to trigger emergency measures, the mayor said.

“I’m not sure what it would take” to shutter the town,” he said. “It would have to be a lot colder than what we’ve experienced here the last few days, anyway.”

International Falls at times has appeared as the coldest place on the U.S. weather map in recent days, although Cotton, Minnesota, was colder on Wednesday at minus 43F (minus 42C), the weather service said.

‘BADGE OF HONOR’

Toughness is part of the lore of International Falls. The late football great Bronko Nagurski, who played fullback for the Chicago Bears in the 1930s and was known for barreling through opponents when he carried the ball, grew up in the town.

“We embrace (the cold) more than anything because it’s like our badge of honor,” said Will Heyer, 23, the sports director for International Falls-based radio stations KGHS and KSDM.

Ultramarathoners gravitate to International Falls at the coldest time of the year for the Arrowhead Ultra, a 135-mile (217- km) race by runners, skiers and bicyclists.

Some 146 participants took off from International Falls on Monday and 52 of them were expected to finish by Wednesday near Tower, Minnesota, race director Ken Krueger said. Tower holds the state record for low temperature at minus 60F (minus 51C) on Feb. 2, 1996.

“That’s what the racers want. They come here for the challenge,” Krueger said, noting that this year’s finish rate of 36 percent was below normal but still better than the low of 20 percent in 2007.

With enough prodding, however, people from International Falls will admit they feel the cold.

“You walk outside and it takes your breath away,” said Kyle Rasmussen, a firefighter engineer. “Your clothes instantly feel cold on your skin. It just saps the heat right out of your bones. Especially when the wind is there. It just cuts right through you.”

Sandy Dexter, 59, the owner of the restaurant Sandy’s Place, said she and her employees amused themselves in the cold on Wednesday by throwing boiling water in the air to create clouds of steam and blowing soap bubbles to watch them freeze.

“It’s a beautiful, sunny day, we’re having fun. We love being the coldest spot in the nation,” Dexter said by phone before adding, “I’ve got two customers shaking their heads at me.”