Avalanche Forecast
Regions: Cascades - West.
Dangerous and complex avalanche conditions exist throughout the region. We have high uncertainty regarding the current conditions in the West Central zone. Carefully evaluate the snowpack and use extra caution on steep unsupported slopes near and above treeline.
Discussion
Snow and Avalanche Discussion
The Mountain Loop area received more than three feet of snow over the weekend, and 2-3 feet of new snow since Monday. The recent snow has fallen at cold temperatures and may be poorly bonded to variable old snow surfaces including surface hoar, firm crusts, and low-density storm snow layers. The most recent snow has fallen with warmer temperatures making a “strong over weak†layering configuration. Avoid wind loaded terrain, especially near ridges.
In the neighboring Stevens Pass and Baker zones, persistent slab problems have developed. Observations from the West Central zone are limited, but we expect similar snowpack structure and buried weak layers may exist in this zone as well. Carefully evaluate the snowpack and choose conservative terrain during this time of elevated danger.
We have received a lot of snow over the past few days. These are the conditions when tree well and snow immersion suffocation accidents occur. Don't travel alone, and keep eyes on your partners. Check out https://www.deepsnowsafety.org/ for more information.Â
Snowpack Discussion
Regional Synopsis coming soon.
Avalanche Problems
Storm Slabs
Several feet of recent low-density storm snow is sitting on variable old snow surfaces. In some areas, buried surface hoar or faceted crystals above a crust are making for very poor bonding. Pay attention to variable loading patterns with shifting wind directions over the next 24 hours. Continue to watch for loose dry avalanches - they could knock you off your feet or pile up debris deeper than you expect. Use small test slopes to assess how the new snow is bonding to itself and older snow layers. Be especially careful of leeward slopes 35 degrees and steeper near and above treeline. Storm slabs can be avoided by sticking to low angle and supported slopes. Cracking or whumphing of the snow are valuable warning signs that anticipated problems are in your terrain.
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