Spring-like diurnal conditions exist and the rating reflects the highest hazard level anticipated during the day. Pay attention to steep south facing slopes as they heat up in the afternoon and possibly destabilize. Give looming cornices a wide berth from above and below.
Summary
Confidence
High - We have a good understanding of the snowpack structure and confidence in the weather forecast
Weather Forecast
A ridge of high pressure will remain anchored over the Interior until Thursday bringing warmer temperatures and sunny skies.Â
The typical spring-like diurnal weather pattern will hold afternoon alpine temperatures near -1 and freezing levels around 1500-2000 m. Overnight periods will see the freezing levels drop back to the valley bottom.
An approaching Pacific frontal system will move onto the coast Wednesday bringing unsettled weather and new snow to the Interior regions by Friday and through the weekend.Â
Avalanche Summary
No new avalanche observations reported on Monday.Â
Several natural and explosives triggered wet loose avalanches up to size 3 on steep solar aspects were reported on Sunday. A large cornice failure (size 2.5) was observed and did not trigger a slab on the slope below. A large glide snow avalanche (size 2.5) was observed on a south aspect at treeline. A small wind slab pocket was triggered by a skier.
Snowpack Summary
Sunny skies and warm temperatures formed sun crusts on solar aspects and at all elevations and up to 2000 m on polar aspects. Dry snow still exists on north aspects at upper elevations. Large cornices loom over alpine ridgetops.
Persistent weak layers of surface hoar, crusts, and/or facets 80-120 cm down have recently been unreactive except for an explosives triggered avalanche in the southeast of the region on Saturday.Â
Terrain and Travel
- Cornices become weak with daytime heating or solar exposure.
- Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Rocks will heat up with daytime warming and may become trigger points for loose wet avalanches
Problems
Cornices
Especially in the southern half of the region where temperatures stay elevated overnight, warm temperatures and sunny skies can increase the likelihood of cornice failures. A cornice fall can be hazardous on its own. Minimize exposure to slopes that have cornices overhead, especially during the heat of the day.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Loose wet avalanches may occur during the heat of the day and primarily on solar aspects. Watch for changing snow surfaces like moist or wet snow, snowballing or natural avalanche activity. Steep slopes and around rocks will be most susceptible to natural avalanche activity.
Large looming cornices may become weak with warming and solar radiation.
Aspects: South East, South, South West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 17th, 2021 4:00PM
