Avalanche Forecast
Regions: Mt Hood.
A mix of winter-like conditions above tree line and wet conditions mainly near and below treeline is expected on Wednesday.
Detailed Forecast
A weak warm front should lift south to north over the Northwest on Wednesday. Little if any rain or snow is indicated by the latest model runs during the daylight hours on Wednesday but there will be a warming trend.
AT Mt Hood watch for possible small leftover wind slab on steep lee slopes near ridges above treeline.
Increasing wet loose avalanches seem possible on steep slopes on Wednesday. Watch for pinwheels and wet snow deeper than a few inches that usually precedes wet loose avalanches. This should be possible all steep slopes from above to below treeline.
An increasing avalanche danger should be seen starting Wednesday night and Thursday as the first in a series of wet and warm fronts moves to the Northwest.
Snowpack Discussion
The weekend of January 24th and 25th a warm and wet weather system caused high snow levels, rain, avalanches and snowpack settlement in the Cascades.
Mild weather with sunny days or minor rain or snow was seen from about January 26th to about February 2nd. This caused more consolidation, stabilizing and the formation of a thick strong stable surface crust in most areas.
The Mt Hood Meadows patrol the past few days has been reporting stable surface crusts and layers of stable consolidated rounded grains or melt forms and crusts in the mid and lower snowpack from multiple warm periods this winter.
NWAC pro-observer CJ Svela also reported a 10 inch thick surface crust at Mt Hood on February 1.
Wetter weather starting today gave about 4 inches of new snow at Mt Hood this morning.
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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, North East, East, South East.
Elevations: Alpine.
Likelihood: Possible
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: Possible
Expected Size: 1 - 1