Avalanche Forecast

Cool NW flow should deliver a taste of winter in late March with light to moderate orographic snow showers at Mt. Hood Thursday. From late Wednesday night through Thursday, new snow should layer right side up as temperatures cool behind the cold front Wednesday night. Deep post-frontal moisture should prevent widespread solar affects, but some daytime warming is likely below treeline at lower elevations Thursday afternoon despite the seasonally cool air mass overhead. 

Persistent and strong westerly winds will primarily load lee slopes near and above treeline, but look for wind affect well into the below treeline band on Mt. Hood. Wind slab will be the primarily hazard on Thursday. By avoiding obviously wind loaded slopes, you can enjoy some fine late season conditions. Firm wind transported snow and snowpack cracking can be good signs of wind slab layers.

Loose dry avalanches should be small but likely on steeper non-solar slopes in non-wind affected terrain. Be aware of terrain traps where even a small loose avalanche could have unintended consequences in the wrong terrain. Loose wet avalanches will not be listed as the primary loose snow avalanche problem, but loose wet avalanches will be possible on steeper solar slopes especially during the odd sunbreak.   

Storm slabs should be a lower concern Thursday. Storm slabs will be more likely in areas that see subtle warming Thursday. During more intense showers Thursday, watch for graupel layers that can become bed surfaces for storm slabs. 

Recently formed cornices have grown large. If traveling along ridgelines, be aware that cornices break much further back than expected and you don't want to go for a ride with a chunk of cornice. Despite the cool weather, cornice releases can be unpredictable during the spring.

Weather and Snowpack

About 4 feet of snowfall accumulated at Mt Hood March 9-15th.

A combination of sun, mild temperatures and then some rain was seen for several days ending about Sunday 3/20. This weather caused about 10-15 inches of consolidation of the recent snow at Mt Hood. Surface snow conditions became highly variable, ranging from cold snow or wind buffed surfaces on non-solar slopes to morning crusts and wet snow on solar slopes.

Older winter avalanche problems of wind and storm slab along the west slopes will have mostly settled and stabilized during the mild weather.

Frequent March storms have built large cornices along ridges in many areas.

A low pressure system crossed the Northwest on Monday and Tuesday. NWAC stations at Mt Hood had about 10 inches of snowfall in the 3 days ending on Wedneday morning.

The mid and lower snowpack along the west slopes should generally be a stable mix of crusts and layers of moist and rounded snow crystals.

Recent Observations

The Mt Hood Meadows pro-patrol on Tuesday morning 3/22 found wind loaded pockets of mostly small wind slab 12-18 inches deep in the above tree line which were stubborn to release by skis. On Tuesday afternoon a recent natural cornice release was seen at about 7000 feet on Marmot Ridge which release a small pocket of wind slab. By Wednesday morning, Meadows pro-patrol found dense wind slab above treeline and on lee slopes only affected by large explosives. Above treeline, satstrugi was widely sculpted into the snow surface with some icy surfaces on windward ridges.