Avalanche Forecast
Issued: Jan 2nd, 2020 5:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is
MBender,
Avalanche Canada
The load on top of weak layers at the base of the snowpack continues to grow. Continue to choose conservative terrain.
Summary
Confidence
No Rating - Forecast snowfall amounts are uncertain.
Weather Forecast
Thursday Night: Scattered flurries. Alpine temperature -12 C. Moderate northwest wind. Freezing level 1600 m.
Friday: Flurries, accumulation 5-10 cm. Alpine temperature -3 C. Moderate to strong west wind. Freezing level 1500 m.
Saturday: Snow, accumulation 5-15 cm. Alpine temperature -5 C. Moderate to strong southwest wind. Freezing level 1100 m.
Sunday: Mainly cloudy with isolated flurries. Alpine temperature -6 C. Moderate southwest wind. Freezing level 1000m.
Avalanche Summary
Explosive control work and other large triggers have consistently produced large deep persistent slab avalanches to size 3 (very large) and larger on all aspects in alpine terrain. Common characteristics of recent avalanches in the region include wide propagation, remote triggers and full depth avalanches scouring away the snowpack to ground.
A couple MIN reports from earlier in the week describe a very large (size 3) deep persistent slab on a well-trafficked slope remote triggered by one or more snowmobiles in the Lang Creek area on Sunday. An adjacent second avalanche may have been triggered sympathetically by the first. On Monday another large (size 2) deep persistent slab was observed just below Gorman Lake. Its trigger is unknown.
Snowpack Summary
10-35 cm of new snow has buried a widespread layer of surface hoar as well as a sun crust on steep south aspects. There are an additional couple of weak surface hoar layers 70-180 cm below the surface. These layers are expected to be progressively gaining strength.
The base of the snowpack in the Purcells is very weak, much weaker than in an average season. This weakness is widespread across all aspects and elevation bands. The basal layer consists of crust, facets and depth hoar.
Recent snowfalls in the past two weeks have overloaded these deeply buried weak layers resulting in numerous very large and destructive avalanches.
Terrain and Travel
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
- Remote triggering is a concern, watch out for adjacent and overhead slopes.
- Storm slabs in motion may step down to deeper layers resulting in large avalanches.
- Be aware of the potential for large avalanches due to the presence of a deep persistent slab.
Valid until: Jan 3rd, 2020 5:00PM
