When the wind has calmed and the snow stops whipping in curls the size of houses, the squeaky chirp of an arctic tern echoes off the mountain face. As you check your gear you hear a grunt like an ox or a bear. Below you on a mountain trail near the tree line, a giant in white fur takes long loping strides, its massive arms swinging. It looks up briefly at you—face barely more human than simian squinched in a frown—and walks on, kicking up three feet of powder with each stride as it makes its way down the mountainside.