Avalanche Forecast

Triggering a storm slab avalanche remains possible on convex slopes steeper than 35 degrees at upper elevations. Older, weak layers buried deep in the snowpack may be a lingering concern, especially in areas further east in the zone. The storm snow is gaining strength, but this major recent storm event should give us pause, especially because all the new snow fell on a thin, early season snowpack. Use snowpack tests and small test slopes to assess the bonding of the snow within storm layers, as well as, older layers. When in doubt, default to lower-angled terrain. Avalanches are unlikely near and below treeline where wet heavy snow has become firm and frozen with cooling temperatures.

Release of a soft cohesive layer (a slab) of new snow that breaks within the storm snow or on the old snow surface. Storm-slab problems typically last between a few hours and few days. Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

You can reduce your risk from Storm Slabs by waiting a day or two after a storm before venturing into steep terrain. Storm slabs are most dangerous on slopes with terrain traps, such as timber, gullies, over cliffs, or terrain features that make it difficult for a rider to escape off the side.

Storm slabs usually stabilize within a few days, and release at or below the trigger point. They exist throughout the terrain, and can be avoided by waiting for the storm snow to stabilize.