Avalanche Forecast
Regions: Stevens Pass.
Avalanche danger will be directly related to the amount of new snow. Conditions are likely to be more dangerous the higher you go. If you find more than 8 inches of new snow or thick, recently formed drifts, avoid steep open slopes.
Discussion
A few small wet loose avalanches were observed during the later afternoon on New Years Eve in the Stevens Pass area. This should be a thing of the past at least for Thursday, as colder temperatures cause the snowpack at lower elevations to freeze up. The inch or two of new snow was observed to be bonding well to old surfaces, at least up to mid 5,000ft elevations. The big question is how much snow will fall at Stevens Pass, as a Puget Sound Convergence Zone looks to set up Wednesday night into Thursday. The avalanche forecast hinges on this affecting the area. If it doesn't materialize, avalanche danger may be lower than anticipated.Â
Recently formed drifts. Southeast facing slope at 5,100ft near Stevens Pass Mountain Resort. January 1, 2020. Photo: Matt Primomo
Snowpack Discussion
New Regional Synopsis coming soon. We update the Regional Synopsis every Thursday at 6 pm.
Avalanche Problems
Storm Slabs
Snowfall may accumulate rapidly overnight and during the day on Thursday. Avalanches may be bigger and more dangerous the higher you go. Winds will form deep drifts on leeward sides of ridges and terrain features at upper elevations. These drifts may be disguised by new snow without much wind. Cracking in the snow or fresh avalanches are danger signs. Use tests and small test slopes to check how easily the snow can slide. Check for poor bonds at interfaces within the new snow. At higher elevations, check bonding between the new and old snow.
Use caution on slopes 35 degrees and steeper where you find more than 6 inches of new snow. Be extra cautious around terrain traps such as gullies, rocks, and cliffs where even a small avalanche could have serious consequences.
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.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 1