Avalanche Forecast
Issued: Jan 9th, 2021 4:30PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Persistent Slabs and Deep Persistent Slabs.
jesse milner,
Winds have diminished except for the very high alpine but the wind-slabs have formed from previous days. Natural avalanche activity has decreased yet conservative terrain selection is advised, assess every slope and human triggering remains possible.
Summary
Weather Forecast
Sunday: Mainly cloudy with isolated flurries. High -7. Wind SW: 20-40 km/h.
Monday: Flurries. 8 cm. Low -8, High -6. Wind SW: 25 km/h gusting to 80 km/h
Tuesday: Periods of snow. Accumulation: 16 cm. Low -10, High -5. Wind SW: 20 km/h gusting to 45 km/h.
Snowpack Summary
The top layer is 40cm of new snow from Jan 3rd which has settled down to 20-30cm in sheltered spots or was redistributed by SW winds into wind-slabs at higher elevations. It overlies a sporadically distributed surface hoar and facet layer down 40-70cm. The mid-pack is supportive except in shallow locations. The bottom is weak facets and depth hoar.
Avalanche Summary
Saturday's flight and weather station service the team did not observe any new avalanches with excellent visibility and lots of terrain covered. Wednesday's patrol to the Icefield's had one size 3, N aspect, high alpine, 1m thick and 300m wide on the backside of Mushroom peak being a wind-loaded spot. Use Mountain Information Network to report.
Confidence
Timing, track, or intensity of incoming weather system is uncertain on Monday
Problems
Wind Slabs
Periodic SW winds continue to form wind slabs treeline and above. They appear to be stubborn with no natural activity observed the past 4 days but be vigilant for human triggering to remain possible. Most caution in the high alpine.
- Use caution in lee areas. Recent wind loading has created reactive slabs.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Use caution around thin to thick areas where buried deeper weak layers could be triggered. The surface hoar layer down 40-70cm seems unreactive and spotty distribution but keep it on your radar.
- Dig down to find and test weak layers before committing to a line.
Aspects: All aspects.
Elevations: Treeline, Below Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
When the snowpack is thick, this weakness should be well bridged and less susceptible to triggering. Triggering this deep layer would be low probability but high consequence.
- Avoid thin, rocky or unsupported slopes.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 10th, 2021 4:00PM
