Avalanche Forecast
Issued: Apr 11th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Loose Wet, Cornices and Wind Slabs.
cgarritty,
Avalanche Canada
Tune in and anticipate the effects of warming as you travel. It will affect increasingly high elevations and shaded aspects over the coming days. Be especially wary of slopes with cornices above them.
Summary
Confidence
High -
Weather Forecast
Sunday night: Mainly clear. Light northeast winds increasing into the morning.
Monday: Sunny. Light to moderate northeast winds. Alpine high temperatures around -4 with freezing levels to 1600 metres.
Tuesday: Sunny. Light to moderate northeast winds, increasing over the day and overnight. Alpine high temperatures around 0 with freezing levels to 2100 metres.
Wednesday: Sunny. Moderate northeast winds. Alpine high temperatures around +4 with freezing levels to 2500 metres.
Avalanche Summary
Saturday's MIN was active! Several users in the region and many more in the neighbouring Sea to Sky and South Coast proper encountered unstable snow conditions. Avalanche activity appears to have been limited to the depth of our latest storm snow.
Looking forward, Monday's concerns should be limited to lingering wind slabs and predictable wet loose activity connected to daytime warming. Tuesday ushers in the start of a dramatic warming trend that will likely expand the extent of wet loose concerns to higher elevation, more shaded aspects and may eventually test deeper snowpack layers.
Snowpack Summary
New surface melt-freeze crusts formed on many solar aspects by the end of the day Saturday atop 10-20 cm of new snow that fell in the north of the region through Friday night, closer to 20-30 cm near the Coquihalla (amounts taper off with elevation). Moderate to strong southwest winds accompanied the snowfall, followed by a lighter northwest flow, leaving behind varying levels of wind effect on many aspects in open terrain.
For the most part the new snow buried (and was reactive over) recent solar and temperature crusts, but it may have added to dry settled snow on higher shaded aspects.
Solar warming will break down surface crusts and encourage wet loose releases -both natural and human triggered- each day on solar aspects and increasingly toward shaded alpine terrain as freezing levels march upward over the coming days.
Cornices are large and looming along ridgelines and they formed fragile new growth during the storm. Their release is unpredictable but increases in likelihood with daytime warming, requiring a large berth if you're travelling above or below them.
Terrain and Travel
- Loose avalanches may start small but they can grow and push you into dangerous terrain.
- Pay attention to cornices and give them a wide berth when traveling on or below ridges.
- Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
Problems
Loose Wet
Surface snow will lose cohesion and become unstable with solar warming during the day. Avoid exposing yourself to terrain where a small wet loose release could have big consequences.
Aspects: South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large and looming along many ridgelines, and have likely formed fragile new growth with recent snow and wind. They grow increasingly unstable during periods of warming.
Aspects: North, North East, East, West, North West.
Elevations: Alpine.
Likelihood
Expected Size
Wind Slabs
Isolated wind slabs may still react to human triggering in steep features at ridgecrest.
Aspects: All aspects.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 12th, 2021 4:00PM
