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
Weather Forecast
Thursday Night: WARM. Freezing levels stationary near 3000 m and forecast to drop to 2000 m by mid- morning Friday. Ridgetop winds light from the southwest.
Friday: Cloudy with possible sunny breaks. Up to 10 cm of new snow at upper elevations and light ridgetop wind from the southwest. Freezing levels dropping to 2000 m by 10 am.
Saturday: Cloudy with sunny periods. New snow 5-10 cm and freezing levels 1200 m. Alpine temperatures near -8 C and ridgetop winds light from the northwest.
Sunday: Mix of sun and cloud. Chance of flurries up to 5 cm. Freezing level near 1200 m and alpine temperatures -8 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. An older (occurred on April 5th) persistent slab was reported size 2.5, failed on the late March crust on a southwest aspect near 2200 m. Several human triggered size 2 slab avalanches were also reported.
Monday and Tuesday saw evidence of a widespread natural avalanche cycle up to size 3 but the average storm/ wind slabs were reported to size 2 and failed in the recent storm snow. Some larger avalanches may have failed on the end of March melt-freeze crust. Most notable was a natural size 3.5 storm slab that started at 2600 m and ran to the valley bottom.
Snowpack Summary
Moist snow surfaces exists up to 2000 m on most aspects and to ridgetop on solar slopes. This will likely exist at higher elevations by Friday.
15 to 30 cm of storm snow has buried multiple crusts in the upper snowpack. Moderate southwest wind has redistributed some of the new storm snow in exposed high elevation terrain forming wind slabs and large cornices.
The new snow brings 60-80 cm above a crust from late March. This crust is present on all aspects up to an elevation of 2600 m and has shown avalanche activity over the past few days.
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.
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.
- In times of uncertainty conservative terrain choices are our best defense.
- 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 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. There is a lot of uncertainty with this interface and whether it will wake up.
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. The 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.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 8th, 2022 4:00PM
