Kevin Bjella, now an engineer at the Cold Regions Research and Engineering Laboratory in Alaska, spent the winters of 2001 and 2002 at Amundsen-Scott as a carpenter. His recollection of joining the 300 Club highlights the downright hazardous nature of the challenge. “It’s not that far of a distance” from the station to the ceremonial pole, he told me, “but when it’s dark, and a hundred below, and people are naked, the safety aspect is really huge.” Most people do the challenge in groups, and usually there are helpful bystanders who line up outside the station with flashlights. A fair bit of anticipation precedes the event; the temperature only drops below -100 a few times each winter, and when it does, you’ve got to be ready to go.

Inside the station, key weather information is displayed on a video screen. It’s usually around late July or August when the “winter-overs” start watching the screen more closely in anticipation of a -100 degree day. When the timing and temperature were right one weekend in 2001, Bjella recalled, he and eight others—“pretty equally split, men and women”—went up to the second floor of "the dome," the station's iconic building that was demolished in 2009, and got in the sauna. “I remember spending something like 20 minutes or half an hour in the sauna, [although] it’s supposed to be 200 degrees. I can’t believe I spent that long in a 200-degree sauna, but maybe it was just psychological, knowing we had to really get warmed up.”

“And then we went and did it, wearing just our bunny boots,” said Bjella, referring to the white rubber boots that the U.S. military issues for use in the extreme cold, and that nearly everyone wears in Antarctica. “We put on the bunny boots and just ran out of the sauna” to the floor of the dome, and then up a long ramp, “like a big white snow ramp,” that spans about 50 yards from the door of the dome to the ice of the Antarctic plateau.

“The physiological altitude there is pretty intense,” he added (the plateau is almost 10,000 feet above sea level). Despite being physically fit and having grown up at an altitude of 7,000 feet in Colorado, Bjella “never really acclimated” to Antarctica. The cold air and the low pressure combine to produce a “physiological altitude” that exceeds the 10,000-foot physical altitude and changes every day according to the barometric pressure. Even after being at the South Pole for a few months, Bjella and others still found themselves getting winded, on occasion, just by walking up and down steps. And running up the ramp to the ice during the 300 challenge was exhausting.

“You get to the top of the ramp and you’re winded,” he recalled. And even then, participants still have about 100 yards to go to get to the Ceremonial Pole and another 100 yards to run on the way back— provided they don’t add extra yards to their trip by running off course.

When Kris Perry, who lives and works in Alaska now, did the 300 challenge for the first time, he walked right past the pole. He was wearing a headlamp, but the pole was just outside the light it cast, and he didn’t realize his mistake until he had missed the spot by at least 20 yards.