Avalanche Forecast
Regions: Mt Hood.
The avalanche danger should decrease further on Monday. E-SE winds may distribute shallow amounts of recent snow onto westerly aspects above treeline. If rain is more intense than forecast in the below treeline elevation band, watch for loose wet avalanches on steeper slopes.
Detailed Forecast
Increasing cloud cover should quickly spread over Mt. Hood Sunday night with periods of light rain or snow developing during the day on Monday. Offshore gradients will create locally breezy east winds Monday. Â Â
The avalanche danger should decrease further on Monday. Light to locally moderate E-SE winds may distribute shallow amounts of recent snow onto westerly aspects mainly above treeline. Older wind slab may linger on NW to SE aspects. Watch for firmer wind transported snow on all aspects, especially in areas of complex terrain.Â
Small loose wet avalanches are considered unlikely Monday due to increasing clouds with only very light precipitation expected. If rain is more intense than forecast in the below treeline elevation band, watch for loose wet avalanches on steeper slopes.Â
It is always a good plan to travel well back from ridges, suspected of cornice formation, or on steep slopes below cornices.
Snowpack Discussion
Weather and Snowpack
The first week or so of March was very cool and snowy. NWAC stations at Mt Hood piled up about 6-7 ft of snow.
The 2nd week of March was equally active with non-stop Pacific frontal systems pummeling the PNW. Unfortunately these systems delivered far more rain than snow. At least two regional avalanche cycles occurred during the stretch. Significant snowpack consolidation occurred over this period due to rainfall and warmer temperatures.Â
After a short respite from the active weather pattern on Thursday, another strong low pressure system brought about an inch of predominately rain to the NWAC Mt. Hood stations Friday night and Saturday morning. Rapid cooling late Saturday morning was followed by snow showers with light new snow accumulation. Strong W-SW winds were transporting new snow above treeline by mid-day Saturday. Sunday was cool with light winds and mostly sunny skies at Mt. Hood. Â
Recent Observations
Mt. Hood Meadows pro-patrol reported a switch from rain to snow at mid-mountain by noon Saturday with strong W-SW winds beginning to build fresh new wind slab above treeline.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.
Likelihood: Possible
Expected Size: 1 - 1