Avalanche Forecast
Regions: Mt Hood.
Expect quickly escalating avalanche danger as one travels further into the above treeline band Monday due to sensitive storm and wind slabs, mainly on lee easterly aspects. Small loose wet avalanches are also possible near and above treeline.
Detailed Forecast
An incoming frontal system will bring light to occasionally moderate rain and snow to the Mt. Hood area beginning mid-morning on Monday. Snow levels should quickly rise to around 7000 feet by late morning or mid-day. Shallow storm and wind slabs, especially on lee aspects should become sensitive due to rising freezing levels and rainfall, releasing on storm layers consisting of new snow from earlier Monday and Sunday's frontal system.Â
Although new storm and wind slabs are expected to be shallow, expect quickly escalating avalanche danger as one travels further into the above treeline band Monday.  Â
Small loose wet avalanches are most likely near treeline where there has been less wind effect.
Below treeline, light to moderate rain should have little impact on the avalanche danger.Â
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Snowpack Discussion
After last weekend's rain (Jan 24-25th), predominately mild or sunny weather settled in during the work week. A frontal system crossed the PNW on Sunday, producing light to moderate amounts of new snow mainly above 6000 ft with moderate westerly transport winds above treeline.
No new avalanches have been reported over the last week.Â
Overall the snow pack at Mt Hood should predominately consist of stable consolidated rounded grains or melt form layers and crusts from warm periods so far this winter.
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: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1
Loose Wet
Release of wet unconsolidated snow or slush. These avalanches typically occur within layers of wet snow near the surface of the snowpack, but they may quickly gouge into lower snowpack layers. Like Loose Dry avalanches, they start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. They generally move slowly, but can contain enough mass to cause significant damage to trees, cars or buildings. Other names for loose-wet avalanches include point-release avalanches or sluffs. Loose Wet avalanches can trigger slab avalanches that break into deeper snow layers.
Travel when the snow surface is colder and stronger. Plan your trips to avoid crossing on or under very steep slopes in the afternoon. Move to colder, shadier slopes once the snow surface turns slushly. Avoid steep, sunlit slopes above terrain traps, cliffs areas and long sustained steep pitches.
Several loose wet avalanches, and lots of pinwheels and roller balls.
Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1