Avalanche Forecast
Regions: Cascades - West.
Dangerous avalanche conditions exist at all elevations. Use extra caution around slopes steeper than 35 degrees. Be especially careful of areas where the wind drifts new snow.
Discussion
Snow and Avalanche Discussion
The Mountain Loop area received more than three feet of snow over the weekend, and two-plus feet of new snow in the past 24 hours. 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 strengthening winds and gradually warmer temperatures making slab avalanches more likely. Avoid wind loaded terrain, especially near ridges, and choose conservative terrain during this time of elevated danger.
Recent avalanche in the Mountain Loop area. 2/10/19 Gary Newberry Photo
Snowpack Discussion
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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. Increasing winds and warming temperatures may likely be enough to tip the balance in some areas. Be especially careful of leeward slopes 35 degrees and steeper near and above treeline. This is a time to dial back and choose conservative terrain. 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.
Loose dry avalanches may be the main concern on steep slopes at low elevations. Watch for fan-shaped avalanches, and avoid hanging out in places where snow normally sheds off steep slopes from above. If the skies clear Wednesday afternoon, expect loose wet activity on steep sun-exposed slopes.
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