Avalanche Forecast
Regions: Mt Hood.
Very dangerous avalanche conditions are expected to develop late Monday night with the danger decreasing during the day on Tuesday. Travel in avalanche terrain is not recommended Tuesday especially above treeline.
Detailed Forecast
The avalanche danger will increase rapidly Monday night as warm frontal precipitation spreads over the area and increases during the early morning hours. Winds will also increase Monday night and stay elevated through Tuesday.  Â
Storm slab instabilities should develop during intense precipitation periods and due to the overall warming trend Monday night. A natural avalanche cycle will likely occur Monday night with the danger decreasing during the day as precipitation tapers down and rising snow levels plateau.Â
New wind slab should develop mainly above treeline on N through SE slopes. Loose wet avalanches will become very likely on steeper slopes in areas that see a switch to rain. Avalanches that begin in the new snow may become larger as they entrain or step down to snowfall received Sunday and Sunday night.Â
Very dangerous avalanche conditions are expected to develop late Monday night with the danger decreasing during the day on Tuesday. Travel in avalanche terrain is not recommended Tuesday especially above treeline.Â
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Snowpack Discussion
Weather and Snowpack
Springlike weather under high pressure Wednesday and Thursday of last week led to abundant sunshine with daytime highs climbing into the 40's and 50's. The fair and mild weather caused thick surface crusts, especially on solar slopes in most areas by Friday and helped stabilize wind slab formed early last week. A weak front brought quite a bit of mostly rain to Mt Hood Friday night to Saturday morning.
A strong Pacific frontal system blew through the Cascades mid-day Sunday. A few inches of wet snow accumulated through the afternoon at Mt. Hood stations, but the strong winds were the main story. The most significant transport winds were from the W-SW and seen in the early afternoon post-frontal passage with gusts in the 40s or 50s near treeline with gusts recorded above 100 mph at the Mt. Hood Meadows Cascade Express station (7300 ft)!Â
The mid and lower snow pack along the west slopes should be a stable mix of crusts and layers of moist and rounded snow crystals.
Recent Observations
The Mt Hood Meadows pro-patrol on Saturday reported little accumulation of new snow and no significant new layers in the above treeline. A wet consolidated upper snow pack was seen in the near and below treeline. Cornice releases gave a couple some size 1 and 2 wind slabs on an east slope at about 6500 feet that is commonly wind loaded.Â
No avalanches were observed on Sunday near and below treeline. Winds were too strong for any person not directly anchored to the mountain to make observations above treeline.Â
On Monday, Mt. Hood Meadows pro-patrol noted some 1-2' soft wind slabs on N-NE slopes above treeline during control work with very small storm slabs noted as well.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.
Elevations: Alpine.
Likelihood: Very Likely
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: Alpine, Treeline.
Likelihood: Likely
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: All elevations.
Likelihood: Likely
Expected Size: 1 - 1