DCHP-1 Online
snow-mushroom 
n. a mushroom-shaped cap of snow that forms on trees, stumps, etc. in regions where snowfall is heavy and constant.
- c1902 At a certain altitude in the mountains, much frequented by game because undisturbed by storms, snow falls--falls--falls, without ceasing, heaping the pines with snow mushrooms, blotting out the sun, cloaking in heavy white flakes the notched bark blazed as a trail.
- 1921 Among the branches huge "snow-bosses" were seen, and "snow-mushrooms" of wondrous shape and bulk were perched upon logs and stumps.
- 1957 [Midwinter in the Rockies and . . . every stump bears a mushroom of snow.]
- c1902 At a certain altitude in the mountains, much frequented by game because undisturbed by storms, snow falls--falls--falls, without ceasing, heaping the pines with snow mushrooms, blotting out the sun, cloaking in heavy white flakes the notched bark blazed as a trail.