Avalanche Forecast
Regions: Mt Hood.
Sunshine and daytime warming may melt and weaken the recent storm snow, especially on solar aspects. Also, watch for weakening cornices and possible wind slabs near ridges.
Detailed Forecast
Partly cloudy skies with sunny periods, cool temperatures and light winds are expected Thursday.Â
In areas that have enough snow cover to provide a bed surface, shallow, loose wet avalanches involving the recent storm snow will be possible with daytime warming. Also, lee easterly aspects may harbor shallow wind slab at higher elevations. Â
Cornices won't be listed as an avalanche problem, but be aware of new cornice growth along ridgelines.
Snowpack problems west of the crest should remain in the upper or surface layers. The mid and lower snowpack west of the crest consists of layers of stable consolidated rounded grains or melt forms and crusts from multiple warm periods this season. Many areas at the lowest elevations do not have enough snow to cause an avalanche danger.
Snowpack Discussion
A vigorous front crossed the Northwest Friday night, causing strong west-southwest winds along with some rain and snow. Snow levels lowered enough by Saturday to produce 2-3 inches of snowfall at higher NWAC stations west of the crest, including including at Mt Hood with likely a few more inches at higher elevations.
The Meadows patrol found some isolated shallow wind slab on Saturday on the northeast slopes above 6500 feet. No new avalanche problems were reported during the mostly sunny and mild weather conditions Sunday and Monday.Â
Snow levels fell quickly after a front moved through early Tuesday morning. Snow showers Tuesday afternoon through Wednesday have deposited a total of about 6 to 10 inches of snow near and above treeline along with moderate westerly transport winds. Patrol at Mt Hood Meadows Wednesday reported that the storm snow was surprisingly less reactive than anticipated. The storm snow produced some 6-12 inch loose or very soft slab avalanches releases from explosive control with no ski released slides.  Â
Avalanche Problems
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: East, South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1
Wind Slabs
Release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind 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.
Wind Slabs form in specific areas, and are confined to lee and cross-loaded terrain features. They can be avoided by sticking to sheltered or wind-scoured areas..
Wind Slab avalanche. Winds blew from left to right. The area above the ridge has been scoured, and the snow drifted into a wind slab on the slope below.
Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas.
Aspects: North, North East, East, South East.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1
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