Back to my exploration of Stephen Donaldson’s extensive vocabulary (while I’m waiting for photos to upload and replies to a query on This one was used in its plural form in Fatal Revenant.

sas·tru·ga /ˈsæstrəgə, ˈsɑstrə-, sæˈstru-, sɑ-/

–noun, plural -gi /-gi/
Usually, sastrugi. ridges of snow formed on a snowfield by the action of the wind.

Also, zastruga.

[Origin: 1830–40; < G < dial. Russ. zastrúga, n. deriv. of zastrugátʾ, zastrogátʾ to plane, shave down (wood), equiv. to za– perfective v. prefix + strugátʾ, strogátʾ to plane, smooth (wood)]