Mt Hood

Watch for developing storm slabs, wind slabs and possible buried surface hoar, especially in areas receiving the heaviest snowfall with the strongest winds, such as at higher elevations. Choose very conservative terrain. 

Increasing storm conditions Saturday. Light rain and snow should increase Saturday morning through the day, becoming moderate to heavy with increasing westerly crest level winds. This should build unstable storm and wind slab layers through the day, with wind slabs spreading to NE-SE facing exposed terrain, especially below ridges by afternoon. 

Expect dangerous avalanche conditions near and above treeline, especially by late Saturday afternoon. Careful snowpack evaluations, cautious routefinding and conservative decision-making will be essential Saturday. 

A warm plume of moisture moved over the Pacific Northwest last weekend. Exceptionally strong winds and heavy precipitation were recorded at Mt Hood; 9-12 inches of water fell at NWAC stations over 72 hrs ending 4 am Monday, 12/22 along with frequent gusts exceeding 100 mph in the alpine, wow! A natural avalanche cycle occurred on the upper mountain during this storm.   

The frontal system that impacted the area Tuesday evening through Wednesday started warm and ended cold for a right side up layering. Moderate to strong winds turned northwesterly with the cool-down... loading easterly aspects during the day. Winds were SW at the onset of this storm... and above treeline slopes were cross loaded. 

New NWAC pro-observer C.J. Svela reported substantial wind transport Wednesday in White River Canyon in the near and above tree-line elevation bands. This translated to cracking on wind loaded slopes and sensitive cornices in the canyon. 

News arrived from the Mt. Hood Meadow pro-patrol Thursday of a post control release. NW winds and additional snowfall continued to load non-traditional southerly lee slopes. A wind slab avalanche was skier triggered in bounds where 40-60 cm of stiffer snow overlaid a weaker layer at 6600 ft on a southerly aspect. Ski cuts produced few results, but the fracture was able to propagate along this interface in extended column tests.  

Friday was a mostly cool and sunny day, which may have helped to settle recent layers.