Avalanche Forecast
Regions: Mt Hood.
You will be able to trigger avalanches in wind-loaded or steep open slopes at all elevations Thursday. New wind and storm slabs may be found in many locations. These avalanches problems will need time to heal. Stay off of open or wind-loaded slopes over 35 degrees and use travel routes and techniques to minimize your exposure to overhead avalanche terrain.
Detailed Forecast
New and reactive wind and storm slabs formed Wednesday night in many locations. You will still be able to trigger these avalanches on Thursday.
Strong winds Wednesday night will transport storm snow to create hard wind slabs on lee slopes and cross loaded mid-slope features at all elevations. Identify and avoid steep slopes where the wind deposited snow. In some locations these wind slabs may be hidden by soft unconsolidated snow. Use visual clues such as cornices, the lack of snow in the trees, and large snow drifts to indicate wind loading on nearby slopes. Give this avalanche problem a wide berth Thursday. Wind slabs will have the potential to become very large and destructive. Use travel routes and techniques to reduce your exposure to Mt Hood’s very large avalanche paths that originate higher on the mountain.  Â
In wind sheltered locations, you will be able to trigger soft storm slabs up to 14†deep. Stay off of all open slopes greater than 35 degrees. Storm slab layers need time to heal. Be patient as this active avalanche pattern proceeds.
Snowpack Discussion
Wednesday several inches of snow began to fall in the Mt Hood area with increasing winds. This new snow fell on a variety of snow surfaces created during the last several days including crust on sunny aspects, wind featured snow, and unconsolidated surface snow in shaded sheltered areas.
In many locations more than 3’ of snow now sits on a firm buried crust layer (2/17). This crust has been reported up to 6600’ by professionals in the region. There are currently no significant layers of concern below the 2/17 crust.
Observations
On Tuesday, Mt. Hood Meadows pro-patrol reported wind buff and soft wind-blown powder with crusts on sunny aspects.Â
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: All elevations.
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.
Elevations: Treeline, Below Treeline.
Likelihood: Possible
Expected Size: 1 - 1