Avalanche Forecast

Light snow showers will be decreasing and westerly winds will be in the light to moderate range on Wednesday.

Large and stiff wind slabs formed Monday night through Tuesday. These slabs are reactive and continue to build. Expect the improving weather on Wednesday to begin to enable these slabs to heal, but with the cold temperatures, significant time is needed. These slabs may be disguised by new snow.

Storm slabs are less likely to be encountered on Wednesday, but you should keep alert for them. Significant new snow has fallen rapidly at all elevations in some locations. Small slope tests and column tests can help you determine whether slabs have formed. 

Small loose dry avalanches are possible in steeper terrain. Avoid steep slopes where the consequence of an avalanche may be significant.

Monday night brought heavy precipitation tapering to snow showers through Tuesday on a cooling trend, which produced Increasingly low density surface snow up 10+". New snow was generally well-bonded to a forming rain crust present at least up to 6600 ft. However, strong SW winds during this storm loaded leeward N through E aspects with observed hard slabs in this terrain.

During a significant warm up January 28-29th, following a long and stormy period since January 17th, explosives were able to trigger multiple very large avalanches.

The break in the weather allowed good visibility of multiple very large artillery-triggered wind slabs which entrained lots of wet snow and even in one case knocked down timber.

Rain on Saturday morning was followed by cooling, creating a thin, breakable crust in some areas.

Winds throughout this active weather pattern redistributed snow forming deep and firm wind slabs on lee slopes near and above treeline.  

Observations

Mt Hood Meadows Pro Patrol Tuesday reported widespread large and hard wind slabs reactive on north through east aspects, near and above treeline with some small loose dry and storm slab possible to trigger below treeline. A rain crust was present up to 6600 ft.

Mt Hood Meadows Pro Patrol Sunday reported multiple very large artillery-released avalanches with very deep crowns up to 12 ft range, running on steep NE and E-NE terrain above treeline and travelling very long distances, in one case snapping 20+ year old trees. Snow pits in the 5000 and 7000 ft range identified 1 mm rounding, wet facets on top of a 1/18 freezing rain crust as the likely weak-layer/bed surface for these very large slides. Given the large amount of recent wind transport, the depth of this layer varied widely.

A Mt. Hood Meadows Patroller provides scale for the sidewall of one of these very large explosive-triggered avalanches on Mt. Hood.

Mt Hood Meadows Patrol Saturday reported sensitive storm slabs which were entraining snow as they ran. A thin breakable rain crust formed in the morning to 5500 feet. By mid-day additional snow was falling at most elevations.