Avalanche Forecast
Regions: Mt Hood.
Fresh storm and winds slabs will continue to form in the Mt Hood area from yet another round of precipitation Friday afternoon into Saturday morning. Saturday is a time for cautious terrain travel especially above treeline.
Detailed Forecast
New snow falling Friday night into Saturday morning will continue to develop new storm and wind slabs around the Mount Hood backcountry. Watch for wind loaded snow near ridge crest and mid-slope cross-loaded terrain features. Winds will vary with height on Mt. Hood Saturday; expect easterly winds around 5000 feet and W-NW winds in the above treeline and higher elevation bands.Â
Shallow storms slabs will form in wind protected areas. Even small avalanches triggered within the new storm snow may entrain soft snow from earlier in the week causing them to grow larger than anticipated.
Early season snow conditions still exist. Be particularly cautious of creeks as many of them have not become snow covered for the winter.
Snowpack Discussion
Several inches of new snow have accumulated in the Mt Hood area by Friday afternoon with more expected Friday night. Moderate to strong winds accompanying this band of moisture will likely have formed fresh wind slabs on lee slopes near and above treeline.
Around a foot of recent snow now sits atop Monday’s freezing rain layer. However due to significant wind transportation of snow especially near and above treeline, height of snow can vary dramatically across terrain.
No recent activity avalanche has been reported in the area.
Observations
Backcountry observations from Thursday confirm the wind redistribution of snow, with bare ridges and wind slabs on lee slopes observed.
Mt Hood Meadows pro patrol reported wind slabs near and above treeline formed earlier in the week. Control efforts on wind slabs within the ski area produced limited results.
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, 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