MOUNTAIN VILLAGE — Francis Waskey's house used to stand four feet above ground on wooden stilts. Now, the mud underneath it has swallowed them whole. As the posts sank over the years into the thawing, carbon-rich frozen soil known as permafrost, Waskey tried propping up the 28-by-36-foot wooden structure with two empty propane tanks, to no avail. The ground shifted so much that the vinyl floor split apart. Nails popped out of the floorboards. The windows shattered, leaving Waskey — a Yupik native who grew up in the home with his family and remained after his parents passed — with icy drafts through subzero winters.

As a construction team used crowbars to pull plywood from the walls, the workers unearthed the source of a musty stench: black mold swirling through spongy yellow insulation like marble cake, so bad that Waskey says taking the stairs now leaves him winded. He has lived here his entire life.