Flathead Range & Glacier NP

Increasing winds may drift snow into slabs large enough to bury and injure you. These will form on the leeward side of ridges and gullies. Find safer riding conditions on slopes sheltered from the wind. Keep slope angles less than 35 degrees if you see signs of shooting cracks and recent avalanches.

On Monday, a rider triggered an avalanche in the southern Whitefish Range (see photo below). The slab was not large enough to bury a person, but could have been consequential if it knocked someone into a tree well. Other observations from the Whitefish Range and Glacier National Park reported recent avalanches that likely occurred Saturday or Sunday. Riders found good and safe riding in parts of the Flathead Range on slopes with mellow slope angles. Total snow accumulations did not reach forecast amounts, and winds did not pick up until later into the evening.

Weather models are showing an uptick in wind speeds throughout the day. Expect to see signs of blowing snow and active wind loading onto easterly facing slopes. The wind drifted snow today may begin to form a more cohesive slab on top of this morning's snow surface. After partly clear conditions overnight, that surface could consist of a layer of fine-grained, near-surface facets. Clancy found a similar layer buried about a foot deep on Mt. Edwards in Glacier National Park that was likely buried 12/18. This layer is the likely failure plane of the small, human-triggered avalanche in the Whitefish Range Monday. We will continue to monitor these potentially weak interfaces. Your observations are crucial to an accurate forecast. We thank everyone who is sending in observations and hope that more continue to do so.