DULUTH — Lauri Olson-Hohman's cherry red swimsuit was a sharp contrast to the snow along the shore of Canal Park beach, but only until she stepped into the icy water of Lake Superior on a Sunday evening in mid-February.

Olson-Hohman called to others on the shore — dozens who, like her, were dressed in a mix of beachwear and winterwear. Crocs and wool socks. Bikinis and beanies. Swim trunks and diving booties.

"Better hurry up," she said playfully. "The water is getting warm."

At 37 degrees, it was just slightly cooler than the air temperature that day. But that didn't dissuade the cold-water immersion practitioners, who seem to have an internal tug toward the lake.

More than 40 people showed up for a group dip set up by the Cold Water Dolphins — including veterans like Olson-Hohman (who took a dip in Lake Superior every day for 150 days straight) to the cold-water curious twentysomething Orion Sorrell, one of several newbies that day. (His explanation: "I've been craving intensity.")

Cold-water immersion holes have opened up on Twin Cities lakes and the phenomenon is gaining popularity in other cold-weather locales. But the coldest of the Great Lakes offers a special challenge.

Almost every day, a member of the Cold Water Dolphins Facebook group, run by Loralee Pasley, posts a time and place for a meetup. Popular spots include Brighton Beach near Scenic Hwy. 61, Endion Station in Canal Park, or a semi-secret neighborhood beach on 42nd Avenue E. It's easy to draw dippers from among the group's 300 people. There are a half-dozen who are almost always game.

Recently a trio met on a windy afternoon for a happy hour dip. Another group of nearly 20 navigated past a rind of crunchy ankle-deep snow along the shoreline. In the past month, one planned dip was thwarted when the wind brought plates of ice to the water's edge, making the beach inaccessible.

Pasley, who teaches yoga and breathwork, started taking cold-water baths after attending a conference that featured Wim Hof. Known as "The Iceman," the Dutch motivational speaker and extreme-weather athlete promotes a combination of breathing and cold-water exposure to address physical and mental health issues. Pasley credits Hof's instruction with helping her break through a deep depression.

Pasley already was a cold-water enthusiast when she started the Facebook group for a practical reason: Safety. Lake Superior is unpredictable. Hypothermia is a genuine threat. And it's also easier to walk into 37-degree water with support.

The group has grown by word-of-mouth. At each meet-up, Pasley coaches first-timers and cheers those taking the quickest of dips. She keeps a watch to monitor how much time dippers spend in the water, watching for signs of hypothermia. She also sticks around afterward to collect forgotten gloves, hats and yoga mats.

Benefits and risks

Libby Gaalaas was intrigued by cold-water immersion when she was invited to a beach party thrown by Pasley in March 2021. Gaalaas had spent a decade as a once-a-year Polar Plunger.

"I dreaded jumping into the hole they would cut out of the ice," she said. "But afterward, every single time, was a feeling that can't be re-created by anything else other than getting into cold water."

That beach party turned into a commitment for Gaalaas. Now she does cold-water dips every weekend.

Members of the Cold Water Dolphins say immersion offers mental health benefits or reduces inflammation, that it allows them to commune with nature or cultivate a cold-weather hobby.

"For me, it's a challenge," said Melissa Cedars. "I want to prove that I can do it. It's a unique thing — 'I'm going to go into Lake Superior in the winter.' Who does that?"

Hydrotherapy has been used for centuries to heal bodies, according to Dr. Shannon May, at Nourish Natural Health Clinic in Duluth. Blood vessels constrict in the cold water and, in narrowing, blood is pushed to the core organs.

"When you move blood to core organs, it gathers more oxygen and nutrients," May said. "As soon as you emerge, they dilate and expand. The oxygen and nutrient-rich blood comes back to all of your tissues. That moves waste products, lactic acid and lowers inflammation."

Over time, advocates say, this can make blood vessels more efficient. But while there is anecdotal evidence of health benefits, May points out that there is little medical research on the practice. The shock of cold water can do more harm than good, she said. People with heart issues should avoid it. And hypothermia can slow faculties and cause a dangerous drop in body temperature.

That doesn't seem to keep the Cold Water Dolphins out of the water.

On that day in February, dippers eagerly moved toward the water, leaving behind what they'd need when they emerged: a yoga mat to stand on, a towel to wrap in or, in one case, a vintage pink robe to zip into.

Once in the water, the dippers crouched down to submerge themselves up to their chests, keeping their gloved hands in the air and their stocking caps pulled over their ears. Some lingered for minutes, others were in and out in seconds.

After their immersion, they stripped out of wet clothes, toweled off, dressed and compared experiences.

"My skin feels weird," Eric Torvinen said, "but I'm not cold."

Olson-Hohman paused, standing barefoot on the beach.

"I'm higher than a kite right now," she said. It's a euphoric feeling that she expected would last — at least until she was fully warm again.