Avalanche Forecast
Issued: Dec 22nd, 2020 4:43PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Storm Slabs.
Stephen Holeczi,
Avalanche control Mt Whymper, Vermillion Peak and Mt. Simpson Wednesday on Hwy 93 S. No activities in these areas. Give the new load some time to adjust.
Summary
Weather Forecast
No new snow is expected over the next few days. On Wednesday NW winds will pick up in the afternoon into the strong range at 3000m. Temperatures will drop to -15C or lower in some areas Wed. AM, and alpine temperatures slightly warmer.
Snowpack Summary
A 10-15 cm over the last 24 hours which his was makes for 60+ cm over the last week in the region. The Dec 13 and Dec 7 sun crust/surface hoar/facet layers are down ~ 60cm and ~90 cm respectively. The height of snow at tree line is 80-150cm.
Avalanche Summary
Avalanche control Tuesday in Yoho produced slides up to size 3. Many were starting as storm slabs and propagating other slabs at treeline. Further East deeper releases were seen, where upslope snow dumped over 30cm
Confidence
Problems
Persistent Slabs
Avalanches were observed on Tuesday that likely initiated on the Dec. 7th and 13th surface hoar/facet/sun crust layers. These are located approximately 60-90cm down in the snowpack.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Storm Slabs
Storm slabs 20-30cm thick were observed on Tuesday. These will likely settle out fairly soon but if triggered can step down to deeper persistent layers.
- If triggered the storm slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Dec 23rd, 2020 4:00PM
