Avalanche Forecast
Issued: Dec 3rd, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Loose Wet.
swerner,
Avalanche Canada
The heat is on! The impact of the afternoon sun and warm temperatures could bump up the avalanche danger to HIGH. Watch for signs of instability and be conservative with your terrain selection.
Summary
Confidence
Moderate - Uncertainty is due to limitations in the field data.
Weather Forecast
A warm air mass will invade the South Coast mountains on Friday bringing warm temperatures and sunshine until Sunday.
Friday: A mix of sun and cloud. Ridgetop wind generally light with strong gusts from the South. Alpine temperatures +8 degrees and freezing levels 3100 m.
Saturday: Sunny with alpine temperatures near +9 degrees and freezing levels 3300 m. Ridgetop winds 25-40 km/h. from the southeast.
Sunday: Cloudy with light precipitation. Ridgetop wind 20-30 km/hr and freezing levels falling to 1900 m.
Avalanche Summary
No new avalanches were reported on Thursday. However, glide cracks did start to open up on the North Shore Mountains.
On Wednesday, numerous slab avalanches and loose wet avalanches were reported at treeline elevations and associated with the rapid warming. An older and larger natural avalanche cycle up to size 3.5 (from last week's storm) was also reported from alpine and treeline elevations.Â
As warm air and sunshine hit the region again Friday and Saturday I expect more natural avalanche activity to occur. The longer the heat sticks around the deeper it drives into the snowpack potentially initiating larger avalanches.Â
Have you been out and about in the mountains? If so please submit to the Mountain Information Network (MIN). It doesn't have to be technical it can be as simple as a photo. Photos are especially helpful! Sending out a big thank you to the already submitted MIN's this season. Thanks everyone!
Snowpack Summary
Recent sun and very warm alpine temperatures have had the greatest impact on the snowpack. This rapid warming likely increased slab development above 1300 m. Deep pockets of wind slab may linger on leeward slopes at upper elevations.Â
Below 1200 m a soggy snowpack may exist. Cooler temperatures overnight may form a crust on all aspects and elevations but I suspect with the continued warming that crust will disappear quickly and make for a wet upper snowpack.
Snowpack depth rapidly changes with elevation and the snow line currently sits at around 900 m. Its near 100 cm around 1000 m between 150 to 200 cm near the mountain tops.
Terrain and Travel
- Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
- Loose avalanches may start small but they can grow and push you into dangerous terrain.
- Back off slopes as the surface becomes moist or wet with rising temperatures.
- Be careful as you transition into wind affected terrain.
Problems
Wind Slabs
Northerly aspects in the alpine may see deeper pockets of fresh wind slab where the old storm snow was redistributed. Warm temperatures and solar radiation will continue the rapid settlement and accelerated slab development on all aspects at treeline and above.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Loose Wet
Rapid warming and sunshine will likely release loose wet avalanches. Pinwheeling is a good indicator of this type of instability.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 4th, 2020 4:00PM
