Avalanche Forecast
Regions: Glacier.
Expect a wintery storm slab in the alpine and spring-like wet snow avalanches at treeline and below.
Re-evaluate your mindset as your travel through different elevation bands- expect variability!
Confidence
Moderate
Avalanche Summary
Several loose moist avalanches and a few cornice failures were observed from steep north aspects today, up to size 2.0.
Thursday, a group boot-packing on Grizzly Mountain triggered a size 2.0 windslab in a variable snowpack depth area.
On Wednesday, a skier triggered, size 1 on a SE aspect in the alpine behind Mt Bonney. This was a thin slab (~15cm) above a crevasse. A natural cornice fall avalanche sz 2.5 also occurred off Mt Bonney, MIN.
Snowpack Summary
Last night ~10cm of new snow fell at treeline and above, and up to 5cm of wet snow fell below treeline. The March 31st is down 20-40cm and is comprised of a solid crust on solar aspects and isolated surface hoar/facets on polar aspects.
The mid and lower snowpack is generally strong. However, the basal weakness from November can still be found near the ground in many locations. Be ready for this layer to wake-up in the next few days.
Weather Summary
An Atmospheric River is poised to arrive Sunday afternoon. The track of this storm is quite uncertain, with forecasted snow amounts for Rogers Pass ranging from 25-45cm by Tuesday morning.
Tonight: Trace of snow. Alpine Low -4 °C. Moderate gusting strong SW wind. FZl 1500m
Sun: Snow 12cm (ramping up in the late afternoon). Alp High -1 °C. Mod gusting strong SW wind, FZL 2000m
Mon: Snow 14cm. Alp Low -5 °C, High -2 °C. Light gusting strong SW wind. FZl 1800m
Terrain and Travel Advice
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.
- Be aware of the potential for loose avalanches in steep terrain where snow hasn't formed a slab.
Avalanche Problems
Persistent Slabs
Use caution on solar slopes where a sun crust is present down 20-40 cm. On polar aspects, this interface is spotty surface hoar and facets. The forecasted storm will load this weak layer and increase the likelihood of triggering and expected avalanche size.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5
Storm Slabs
New snow and continued moderate SW winds today are building fresh storm slabs on lee slopes in exposed areas at treeline and above.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5