Avalanche Forecast
Issued: Apr 7th, 2022 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs, Loose Wet and Cornices.
swerner,
Avalanche Canada
The weather pattern right now is dynamic and fast-changing, and we're unsure about how the snowpack will react. During times of uncertainty, lean on a conservative approach to terrain, a cautious mindset, and continually make observations as you travel.
Summary
Confidence
Moderate - Uncertainty is due to how quickly the snowpack will recover and gain strength.
Weather Forecast
Thursday Night: WARM. Freezing levels stationary near 3000 m and are forecast to drop to 2000 m by mid-morning Friday. Ridgetop winds light to moderate from the southwest.
Friday: Cloudy. New snow 10 to 20 cm at upper elevations and light ridgetop wind from the southwest. Freezing levels dropping to 1500 m by the afternoon.Â
Saturday: Cloudy with sunny periods. New snow 5-10 cm and freezing levels 1200 m. Alpine temperatures near -5 C and ridgetop winds light from the northwest.Â
Sunday: Mix of sun and cloud. Chance of flurries up to 5 cm. Freezing level near 1200 m and alpine temperatures -5 C. Ridgetop winds light from the West.
Avalanche Summary
On Wednesday, reports showed a wide range of avalanche activity. A natural storm/ wind slab and wet loose cycle was seen up to size 2.5. A couple of human triggered avalanches up to size 2. Upon further investigation a persistent slab that was reported two days ago failed on the end of March crust and stepped down to the early December rain crust that sits approx. one metre off the ground.
On Tuesday, numerous natural, explosive, and rider-triggered avalanches were reported up to size 3.5. Most of these avalanches failed within the recent storm snow, however, some of the larger ones were reported as a persistent slabs that failed on a buried crust.
Snowpack Summary
Moist snow surfaces exists up to 1700 m on most aspects and to ridgetop on solar slopes. This will likely exist at higher elevations by Friday.
20 to 40 cm of recent storm snow has buried multiple crusts in the upper snowpack. Moderate southwest wind has redistributed some new storm snow in exposed high elevation terrain forming wind slabs and large cornices.Â
The new snow brings 60-80 cm above the crust from late March. This crust is present on all aspects up to an elevation of 2500 m. Large avalanches have failed on this crust over the past few days.Â
The early-December rain crust is approximately a metre off the ground. Large slab avalanches failed on this interface last week following a rain and warming event. This layer may be active with no overnight refreeze and warm weather on Friday.
Terrain and Travel
- 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.
- Choose conservative terrain and watch for clues of instability.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
Problems
Persistent Slabs
60-80 cm of recent storm snow sits above a crust at treeline and above. Warming may consolidate the new snow into a reactive slab, producing large avalanches. Avalanches may start as dry slabs in the alpine but entrain wet snow and run into below treeline elevations.
The warm-up last week produced some deeper and bigger avalanches that ran to the valley bottom. These failed on a December rain crust that exists a metre off the ground. This layer was reactive two days ago in an isolated event.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
No overnight refreeze and warm temperatures may continue to weaken the upper snowpack, creating wet avalanches.
Wet loose avalanche activity will likely decline as temperatures drop and a surface crust forms.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
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
Expected Size
Valid until: Apr 8th, 2022 4:00PM
