Avalanche Forecast
Regions: North Rockies.
The weather pattern right now is fast-changing, and we're unsure about how the snowpack will react. During times of uncertainty, lean on a conservative approach to terrain, and continually make observations as you travel.
The northern tip of the region may see more rain/snow
Confidence
Low - Uncertainty is due to how quickly the snowpack will recover and gain strength. Forecast precipitation (either snow or rain) amounts are uncertain.
Weather Forecast
Thursday Night: Mixed precipitation rain/ snow up to 25 mm in Pine Pass and 5-10 mm in the South. Freezing levels 2500 m and dropping to 1500 m by 4 am Friday. Ridgetop winds light to moderate from the southwest.
Friday: Cloudy. New snow 5 cm and moderate ridgetop wind from the southwest. Freezing levels are forecast to drop to 1200 m.Â
Saturday: Cloudy with sunny periods. New snow 5 to 10 cm and freezing levels 1000 m. Alpine temperatures are near -10 C and ridgetop winds light to moderate from the northwest.Â
Sunday: Mix of sun and cloud. Freezing level near 700 m and alpine temperatures -15 C. Ridgetop winds light from the West.
Avalanche Summary
No reports since last weekend.Â
Warm temperatures, rain and snow may trigger a natural avalanche cycle on Friday.
On Sunday, a small natural wind slab avalanche was observed on a north aspect in the alpine. A rider triggered a small slab avalanche on the same slope. Both avalanches likely occurred on Saturday.
On Saturday, many natural dry loose avalanches were reported in steep terrain, as well as a large cornice failure that released a slab on the slope below.Â
Snowpack Summary
Moist snow may exist up to 1900 m on most aspects and to ridgetop on solar slopes. This may extend to higher elevations by Friday morning.
25 to 50 cm of new storm snow blankets upper elevations with the greater snowfall amounts being in the Renshaw. Light to moderate wind has redistributed the new storm snow in exposed high elevation terrain forming wind slabs and large cornices. The upper 60 cm of the snowpack consists of multiple crusts.Â
50-70 cm of snow sits on the thick melt-freeze crust from late March. There has been no recent avalanche activity reported on this layer.
Terrain and Travel
- Watch for changing conditions today, storm slabs may become increasingly reactive.
- Be aware of the potential for large avalanches due to the presence of a buried crust.
- Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
Avalanche Problems
Storm Slabs
The northern part of the region may see up to 25 cm of new snow in the alpine by mid-morning which may build new storm slabs.
This brings up to 70 cm of consolidated snow above a crust at treeline and above. The recent warming may form a reactive slab on this interface.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2.5
Loose Wet
No overnight refreeze, warm temperatures and rain at lower elevations may weaken the upper snowpack, creating wet avalanches.
Wet loose avalanche activity will likely decline as the temperature drops and a surface crust forms.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood: Possible - Likely
Expected Size: 1 - 2.5
Cornices
Springtime cornices are large and unpredictable. Warming can pack a punch and lead to cornice failures. Give them a wide berth when travelling at ridge crest and avoid overhead exposure.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible
Expected Size: 1.5 - 3