Avalanche Forecast
Regions: Mt Hood.
The avalanche danger at Mt Hood should gradually decrease on Monday. Watch for lingering wind and storm slab especially above treeline.
Detailed Forecast
Light west flow, light snow showers and slightly lower snow levels should be seen at Mt Hood on Monday. This should not build significant new layers. The avalanche danger should gradually decrease on Monday as new layers from Sunday partly stabilize.
Wind slab from Sunday should linger at Mt Hood mainly above treeline on Monday. It is also possible near treeline depending on if there is significant snowfall in this band on Sunday. Watch for firmer wind transported snow on previous lee slopes.
Storm slab from Sunday may linger to some extent at Mt Hood on Monday but will be stabilizing. Watch for cracking and releases on steep sheltered slopes where snowfall exceeded an inch an hour for more than a few hours on Sunday.
The cooling should also cause some good right side up snow conditions on other slopes on Monday.
Snowpack Discussion
Strong southwest flow carried a wet front across the Olympics and Cascades Saturday night. This front tapped subtropical moisture so snow levels got pretty high with about 3.5-4.5Â inches of rain at NWAC sites at Mt Hood.
West southwest flow and mostly moderate showers are occurring at Mt Hood Sunday with slightly lowering snow levels.
NWAC observer CJ Svela was at Timberline on Sunday. He found consolidated P and 1F layers in the top meter of the snowpack. He reported about 8 cm of new snow at 7100 feet.
The mid and lower snowpack at Mt Hood should also mainly consist of melt-freeze crusts and stabilized rounded grain layers from warm periods so far this winter. Persistent weak layers are not expected at Mt Hood.
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
Storm Slabs
Release of a soft cohesive layer (a slab) of new snow that breaks within the storm snow or on the old snow surface. Storm-slab problems typically last between a few hours and few days. Storm-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.
You can reduce your risk from Storm Slabs by waiting a day or two after a storm before venturing into steep terrain. Storm slabs are most dangerous on slopes with terrain traps, such as timber, gullies, over cliffs, or terrain features that make it difficult for a rider to escape off the side.
Storm slabs usually stabilize within a few days, and release at or below the trigger point. They exist throughout the terrain, and can be avoided by waiting for the storm snow to stabilize.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 1 - 1