Avalanche Forecast
Regions: Mt Hood.
Moderate danger does not mean it's OK to let your guard down. Increasingly sensitive avalanche conditions involving generally shallow amounts of new snow are likely on lee slopes near and above treeline as well as loose wet avalanche concerns during sunbreaks and daytime warming Tuesday afternoon. Intense showers may produce unstable graupel layers for future snow to fail on.
Detailed Forecast
A frontal system passing through late Monday night should be followed by orographic showers and a cooling trend at Mt. Hood Tuesday. Showers may be locally intense Tuesday afternoon.Â
Moderate danger does not mean it's OK to let your guard down. Increasingly sensitive avalanche conditions involving generally shallow amounts of new snow are likely on lee slopes near and above treeline as well as loose wet avalanche concerns during sunbreaks and daytime warming Tuesday afternoon. Intense showers may produce unstable graupel layers for future snow to fail on.    Â
Cornices won't be listed as an avalanche problem but be aware of new cornice growth along ridgelines.
Snowpack problems west of the crest for the time being should be in the upper or surface layers. The mid and lower snowpack west of the crest consists of layers of stable consolidated rounded grains or melt forms and crusts from multiple warm periods this winter. Many areas at the lowest elevations do not have enough snow to cause an avalanche danger.
Snowpack Discussion
Winter made a bit of a comeback in the Northwest in mid to late March. Several storms or storm cycles brought heavy snow to the above treeline areas west of the crest especially on the volcanoes.
A vigorous front and short wave crossed the Northwest Friday night causing strong west-southwest winds along with some rain and snow. Snow levels lowered enough by Saturday to produce 2-3 inches of snowfall at higher NWAC stations west of the crest including at Mt Hood with likely a few more inches at higher elevations.
The Meadows patrol found some isolated shallow wind slab on Saturday on northeast slopes above 6500 feet. Mostly sunny and mild weather conditions were seen Sunday and Monday with no new avalanche problems reported.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, 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: East, South East, South, South West, West.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 1 - 1