Avalanche Forecast
Regions: Glacier.
North-facing slopes in the alpine hold the best ski quality, but they also are concealing a reactive surface hoar layer. Folks in and around the region have been caught off-guard by this layer, resulting in several avalanche involvements.
Carefully assess your line for this weak layer before committing.
Confidence
High
Avalanche Summary
One natural glide slab was observed on the 12th. Otherwise, no new natural activity reported since the 10th
On Friday there was a backcountry report of skier triggered sz 2 wind slab on the Dome glacier at 2450 m on a NE asp. This avalanche likely failed on a layer of surface hoar down 15-40 cm
A wide-propagating(~500m) sz 2.5 was also triggered by skiers on Friday up the Bruins Glacier.
Snowpack Summary
Daily melt/freeze cycles are affecting the surface of the snowpack on solar slopes and all aspects BTL, with several crusts of variable strength in the upper snowpack. High alpine, north facing slopes still hold dry snow. A buried surface hoar layer exists down 15-40cm in sheltered north alpine areas above ~2300m. This layer is reactive to human triggering and is catching people off guard.
Below treeline, conditions are variable and challenging travel exists.
Weather Summary
Isolated flurries Tues, then back to sun/cloud and gusty winds for a few days.
Tonight Mainly cloudy, isolated wet flurries. Alp low -1°C. Ridge wind SW 25-35km/h. Freezing Level (FZL) 1900m
Tues Cloudy, some sun, isolated flurries. Alp high 2°C. Wind W 20-35km/h. FZL 2100m
Wed Mix sun & cloud. Alp high -3°C. Wind N 20-45km/h. FZL 1800m
Thurs Sun and cloud. Alp high -1°C. Ridge wind N 15-30km/h. FZL 2000m
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind-affected terrain.
- Be aware of the potential for larger than expected storm slabs due to buried surface hoar.
- A moist or wet snow surface, pinwheeling, and natural avalanches are all indicators of a weakening snowpack.
Avalanche Problems
Wind Slabs
Strong winds Thursday/ Friday formed wind slabs on lee slopes in the alpine. This layer is sitting on a crust and it's able to pick up mass in steep terrain. On high alpine North facing slopes, this wind slab sits on a layer of surface hoar and is producing skier triggered size 2-2.5 avalanches!
Aspects: All aspects.
Elevations: Alpine.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5
Loose Wet
Intense spring sun will weaken the upper snowpack, especially on steep solar slopes. Rider triggering is also possible. Use caution in steep terrain and around terrain traps.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1 - 2