Strong solar radiation and warm temperatures will weaken cornices and the snowpack. Avoid overhead hazard, especially in the afternoon. The danger rating is for the hottest time of the day. Check out this blog on warming and how to stay safe.
Summary
Confidence
Weather Forecast
A ridge of high pressure over the province continues to bring sunny, dry weather. Freezing levels are forecast to steadily rise through the week.
Tuesday night: Clear, light to moderate northeast wind, alpine low -10 C, freezing level around 1500 m except for the west of the region where it will rise to 2200 m.
Wednesday: Sunny, light to moderate northeast wind, alpine high +5 C, freezing level 2600 m.
Thursday: Sunny, light easterly wind, alpine high +10 C, freezing level 2900 m.
Friday: Sunny, calm wind, alpine high +10 C, freezing level 3200 m.
Avalanche Summary
Several small wet loose avalanches to size 1.5 on solar aspects in the alpine were reported on Tuesday. Over the past couple days a couple small wind slab avalanches to size 1.5 released naturally and were triggered by riders.
Several cornices failed recently and did not trigger slabs on slopes below except for a few that triggered size 2 slabs on extremely steep north facing slopes.
On Sunday, numerous small natural wet loose avalanches of size 1.5 were reported on solar aspects.
Snowpack Summary
The snow surface consists of a melt-freeze crust on solar aspects and shaded aspects below 1200 m which transitions into moist or wet snow during the day. Dry snow can still be found on northerly aspects at treeline and in the alpine. 20-40 cm of recent snow has formed isolated pockets of wind slab on leeward slopes and behind terrain features. This recent snow sits on a series of melt-freeze crusts on all aspects below 1900 m and southerly aspects to mountain top. Reports indicate snow is bonding well at these interfaces. On North aspects in the alpine, the recent snow sits on dry wintery snow surfaces and possibly surface hoar on wind-sheltered slopes.
Cornices are large and become more and more fragile with warm temperatures. Many natural cornice failures were observed recently.
Warm temperatures and rising freezing levels might wake up old persistent weak layers, including a few crusts buried over the last month as well as a facet layer 150 cm deep from the mid-February cold snap.
Terrain and Travel
- Use extra caution around cornices: they are large, fragile, and can trigger slabs on slopes below.
- Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
- Loose avalanches may start small but they can grow and push you into dangerous terrain.
- The likelihood of deep persistent slab avalanches will increase with each day of warm weather.
Problems
Cornices
Cornices are large and will become more fragile with rising temperatures and sun exposure. Many natural cornice failures were reported recently. Cornice falls are dangerous on their own and they can trigger slabs on slopes below.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Surface snow can quickly lose cohesion and become unstable with strong solar radiation and warm temperatures. Avoid exposing yourself to sunny slopes, especially in the afternoon.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 14th, 2021 4:00PM
