Avalanche Forecast
Regions: Mt Hood.
Even as storm slab avalanche concerns diminish, old wind slab on easterly aspects and new wind slab on south and westerly aspects will require careful terrain management Tuesday.
Detailed Forecast
Moderate to strong east winds should continue through Tuesday under mostly clear skies and cold temperatures. When traveling into the near and above treeline zones, be prepared for new wind slab formation on more southerly and westerly aspects. Older wind slab on more westerly aspects may still be sensitive in certain areas. Treat wind loaded slopes with caution, it is difficult to determine how sensitive they are with snowpack tests. Loose dry avalanches are possible in wind sheltered areas below treeline... watch for sluffing on steeper slopes especially above terrain traps.
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Snowpack Discussion
A storm system moved through the Northwest on Saturday and Saturday night delivering some much needed snowfall. West winds changed to northwest, with moderate to heavy snow and a cooling trend. Heavy snowfall continued Sunday and Sunday night with NWAC sites on Mt. Hood picking up about 25-30 inches of storm snow through Monday afternoon!
Mt. Hood Meadows pro patrol found cracking and easy releases of soft and generally shallow wind slab due to the rapid wind loading Monday.  Â
Moderate to strong northwest winds switched to easterly Monday. This should quickly build new wind slab on westerly aspects. Due to the cold temperatures, soft storm slabs are not expected to be a widepsread problem.  The below treeline zone now has enough snow for a loose dry avalanche problem on steeper slopes that are wind sheltered.  Â
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Avalanche Problems
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 East, East, South East, South, South West, West.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 2
Loose Dry
Release of dry unconsolidated snow. These avalanches typically occur within layers of soft snow near the surface of the snowpack. Loose Dry avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs. Loose Dry avalanches can trigger slab avalanches that break into deeper snow layers.
Loose Dry avalanches are usually relatively harmless to people. They can be hazardous if you are caught and carried into or over a terrain trap (e.g. gully, rocks, dense timber, cliff, crevasse) or down a long slope. Avoid traveling in or above terrain traps when Loose Dry avalanches are likely.
Loose Dry avalanche with the characteristic point initiation and fan shape.
Loose dry avalanches exist throughout the terrain, release at or below the trigger point, and can run in densely-treed areas. Avoid very steep slopes and terrain traps such as cliffs, gullies, or tree wells.
Elevations: Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1