Avalanche Forecast
Regions: Mt Hood.
Cold temperatures will help preserve recent storm snow instabilities found on wind loaded aspects near and above treeline. In steep terrain where the new snow lacks a slab structure, watch for small loose dry avalanches near terrain traps like cliff bands where even small avalanches can have big consequences.
Detailed Forecast
Several inches of low density snow may accumulate Monday as a weak front passes through the Cascades. Moderate westerly alpine winds are forecast to decrease slightly Sunday night but should still be strong enough to continue loading lee aspects near and above treeline with plenty of new low density snow available for transport. Storm slabs should be less sensitive on Monday, but sustained cold temperatures will help preserve recent storm snow instabilities. In particular watch for lingering storm or wind slab on lee aspects near and above treeline that can still be human triggered. Only wind slab will be listed in the avalanche problems moving forward.
In steep terrain where the new snow lacks a slab structure, watch for small loose dry avalanches near terrain traps like cliff bands where even small avalanches can have big consequences.   Â
In much of the lower part of the below treeline band there is still insufficient snow for avalanches, so watch for early season travel hazards such as terrain traps, rocks and open creeks.Â
Snowpack Discussion
Weather and Snowpack
A front crossed the Cascades Friday with around 2 inches of new snow reported at NWAC stations on Mt. Hood through early Saturday morning. A warming trend ahead of the front allowed a breakable freezing rain crust to develop up to at least 6800 feet.
A much stronger front sagged south across the area late Saturday night delivering a welcome 1-2 feet of snow at Mt. Hood stations through early afternoon Sunday. This system also ushered in the coldest air mass of the season. Â
Avalanche problems should be confined to the most recent storm snow and  we are not tracking any weak layers in the lower or middle of the snowpack at this time.Â
Recent Observations
Pro-observer Laura Green was touring in Iron Creek Saturday and found a generally stable snowpack with obvious signs of recent wind transport with scoured windward aspects as she traveled near treeline. The Meadows pro-patrol had no significant avalanche control results Saturday.Â
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, North East, East, South East, South.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 1
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: Treeline, Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1