Avalanche Forecast
Regions: Cascades - South East.
Much of the below treeline elevation band does not have enough snow cover to support an avalanche hazard. Shallow and isolated pockets of storm or wind slab may exist near and above treeline. Watch for non-avalanche related hazards such as open creeks and barely buried rocks and trees.
Detailed Forecast
A fresh 2-6" of snow is forecast Sunday night through Monday morning. Scattered snow showers are expected for the remainder of Monday.Â
In the Washington Pass area there is the potential for shallow areas of storm or wind slab predominately near and above treeline although new snow Sunday night should fall with a favorable cooling trend.Â
Outside of Washington Pass, much of the below treeline elevation band does not have enough snow cover to support an avalanche hazard. Shallow and isolated pockets of storm or wind slab may exist near and above treeline. The Moderate hazard will be maintained near and above treeline in part due to the lack of direct observations over the last few days.Â
Watch for the numerous travel hazards such as open creeks, barely buried rocks and trees, and glide cracks, creating poor and challenging travel conditions, especially below treeline.Â
Remember that closed ski areas without avalanche mitigation are equivalent to backcountry terrain! Â
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Snowpack Discussion
New resources within your Avalanche Forecast this season!Â
The Mountain Weather tab will take you to the most recently issued Mountain Weather Forecast. The Observations & Weather Data tab will allow an easy view of the various weather station graphs within your zone of interest and provide easy access to the most recent avalanche and snowpack observations.Â
The great start to the 2017/18 PNW Winter hit the pause button over the last week in the Washington Pass area with only small fluctuations in total snow depth at the Pass during this incredibly active period (see graph). During an extended period of warmth and wet weather in the days leading into Thanksgiving, an initial round of wet snow and glide avalanches occurred, especially on steep unsupported slopes and rock faces (see observation below).Â
Over the weekend, the weather system that brought rain to the rest of the Cascades brought several inches of snow Saturday night through Sunday at Washington Pass. Mixed precipitation or a brief period of rain may have occurred Sunday afternoon as temperatures warmed aloft. Â
Little to no new snowfall was seen for most of the central-east and southeast Cascades over the weekend due to warmer temperatures and a period of rain. Snowdepths are also lower in these areas.Â
Observations
See the recent observations tab for reports of several wet snow avalanches near the WA Pass area as a result of the warming and rain early last week.
Avalanche Problems
Storm Slabs
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: Possible
Expected Size: 1 - 1