Avalanche Forecast
Regions: Glacier.
Reactive storm slabs are propagating widely over a crust on solar aspects at treeline and alpine elevations, minimize your exposure where the sun is warming the snow surface.
Below treeline loose wet avalanches are easily triggered and gain mass quickly as the run on a widespread crust.
Confidence
Moderate
Avalanche Summary
Multiple solar triggered storm slab and loose wet avalanches up to size 3 were observed along the hwy corridor and in the backcountry on Wednesday. These avalanches showed wide propagation failing at the Mar 31 layer and running far into the runout zones. A field team was also able to easily trigger multiple small avalanches in the moist surface snow also failing on a widespread crust below tree line.
Snowpack Summary
35cm of storm snow and strong, gusty SW winds have formed a reactive storm slab, thicker in lee features. This slab is propagating and stepping down to the March 31 layer (crust on solar aspects, facet/surface hoar on polar aspects).
The snowpack is generally strong. However, the Nov 17 basal weakness can still be found near the ground in many locations.
Weather Summary
Calm weather prevails for the remainder of this week with gradually rising freezing levels and some isolated flurries.
Thurs: Mix of sun & cloud, Alp high -5*C, light W winds, 1600m FZL
Fri: Mix of sun & cloud, Alp high -5*C, light SW winds, 1700m
Sat: Cloudy w/ sunny breaks, flurries, Alp High -2*C, light SW winds, FZL 2000m
Terrain and Travel Advice
- Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
Avalanche Problems
Storm Slabs
The recent storm slabs have not yet bonded to the underlying surface and remain reactive to human and natural triggers and have shown wide propagation.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1.5 - 3
Loose Wet
Below tree line the new snow is easy to get moving beneath your feet on steep slopes and quickly gains mass producing heavy, loose wet avalanches.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood: Unlikely - Possible
Expected Size: 1 - 2
Deep Persistent Slabs
There has been no activity on this layer for several weeks, but the recent precipitation and warming temps later this week could be enough to re-activate this layer. Lower, rain-soaked elevations may be more likely to see deep releases to ground.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely
Expected Size: 2 - 4