Leszek Naziemiec is an avid ice swimmer. But even in the midst of summer, the 48-year-old from the northwest Poland village of Kołczewo couldn’t resist a trip through the north Alaska wilderness.

I got the heads-up call the second week of February from Doug in Bethel. The next week was forecast for colder weather and snow. The plan was to go hunting for moose or muskox on sno-gos (the local ...