Avalanche Forecast
Regions: Mt Hood.
A slow improvement should continue, but locally increasing east winds near the crest may begin forming new sensitive slabs on lee, mostly westerly facing terrain, especially below ridges. In the steep wind sheltered terrain, watch for small loose dry avalanches near terrain traps like cliff bands where even small avalanches can have big consequences.
Detailed Forecast
Partly cloudy conditions with cold temperatures are expected through midday Wednesday. This weather should allow for continued very slow settlement of any wind slabs recent formed, allowing for a slow decreasing trend in the avalanche danger overall.Â
By midday Wednesday and into the afternoon, however, expect increasing easterly winds near the crest. Watch for locally increasing winds later Wednesday as the very low density surface snow will be easily transported to lee slopes or cross loaded features and shallow wind slabs may form quickly in exposed terrain.Â
In particular, watch for lingering or newly forming wind slab on lee aspects near and above treeline that may be sensitive to human trigger.Â
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
Even though the lower part of the below treeline band is filling in, watch for early season travel hazards such as barely covered 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 crossed 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. Further showers at cold temperatures deposited an additional 12 inches of snow by Monday evening. Light snow showers Monday night and early Tuesday with light winds added several more inches of low density snow to the already low density snowpack! The most recent snow has not changed the overall danger, that continues to slowly improve. Storm snow amounts have now reached an impressive 2-3 feet or more since late Saturday. 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
Patrol at Mt Hood Meadows Monday and again Tuesday reported only isolated wind slabs in exposed terrain at the upper elevations. These avalanches were fairly shallow within the upper 4-8 inches of snow mostly and released with explosives only. In general, most areas have surface snow conditions lacking slab character with low cohesion snow providing some excellent conditions.Â
Patrol at Mt Hood Meadows Sunday indicated a favorable snowpack profile with very limited slab like character noted, except for isolated features were wind deposited snow produced some very soft slab releases of little consequence. Â
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: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
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