The polar vortex has chilled the nation to the bone. For some people, however, this cold stretch is nothing. To quote a recent Disney princess, the cold never bothered them anyway. For them, this weather isn’t cold. Cold is running into a freezing body of water – maybe wearing a costume, maybe wearing just a swimsuit – submerging themselves in completely and then racing back out again with a brand new layer of icicles.

Some might call that insanity. For the past 15 years, however, Special Olympics Wisconsin has called it the Polar Plunge.

What started in La Crosse back in 1999 has now grown to 12 locations across the state, including a plunge at McKinley Marina right here in Milwaukee on Feb. 15. In order to participate, each brave person – whether they be in a team or participating individually – must raise a minimum of $75 (there are additional prizes for raising more than the requisite amount). Once they’ve registered, signed a waiver and donated their money, come Feb. 15, it’s plunging time.

"They run in, most dunk their heads and bodies into the water and then they run back out," said Kelly Lang, the Regional Director of Development for Special Olympics Wisconsin in the Greater Milwaukee region. "They’re not in there for a very long time, which is very good obviously."

When the plungers run back out, there’s a heated changing tent – as well as a heated entertainment tent featuring food, beverages and a live band – waiting for them back on dry land.

For those more sensitive to insanely cold temperatures, there is also the Too Chicken to Plunge option, where people can raise the $75 minimum and take advantage of everything the event offers without having to brave the freezing water. People can also create teams to either toss their boss, teacher or principals into the McKinley Marina, as well (with the boss or teacher’s permission, of course).

Even with those drier, warmer options, the Polar Plunge in Milwaukee had over 500 plungers last year fling themselves into freezing water.

"I think people just like the adrenaline rush," Lang said. "They keep coming back. We have tons of people who do it year after year."

"Going into the water, you're just hyped up so much from the anticipation and waiting," said Krysten Kirsch, Director of Youth Initiative at Special Olympics Wisconsin and a two-time Polar Plunger. "You're already pretty cold from standing there, waiting for your turn and watching everybody else that when you get into the water, it's pure adrenaline. Coming out then, there's that shock of, 'What did I just do?'"

Of course, it’s all for a good cause. Last year, nearly 10,000 participants across the 12 Wisconsin plunges helped raise more than $1.8 million for the Special Olympics Wisconsin, a year-round sporting organization for those with intellectual disabilities.

"The money that we raise goes toward their competitions and their overall participation in Special Olympics," Lang said.

For 2014, Lang reported that the event is currently trending ahead of most years in terms of both plungers and money raised. Things have slowed down since registration opened for the Polar Plunge, which Lang assumes might have something to do with the legendarily cold winter that’s plagued the Midwest.

"If you haven’t done it before and don’t know what to expect, I think the cold can scare you away," Lang said. "It’s the people who have been doing it for years that know that it’s going to be cold, but there’s fun, warm things to do before and after you plunge. We won’t ever endanger somebody’s safety obviously, and we’ll have a great time whether people get to go in the water or not. But it’d have to be really cold for us to think about cancelling it."

So far, in the 15-year history of the Special Olympics Polar Plunge in Wisconsin, there have been no serious injuries or health risks. Still, the adrenaline rush – from raising money for a good cause or from galloping into a pond of spine-tinglingly cold winter water – is there.

"I want to say people do this because it’s such a good cause and people are willing to do stuff for it," Lang (who admitted she falls on the "Too Chicken to Plunge" side of things) said. "I think it’s half and half. I think some people just love Special Olympics, and then there are the people who just love doing the crazy things to tell people that they’ve done it and can check it off their bucket list."

"It'll add to the excitement to say we went plunging in one of the coldest winters in the last however many years," Kirsch said.

The Polar Plunge still seems insane, but I suppose if you’re going to be cold this winter, it might as well be to help others.