Avalanche Forecast
Issued: Jan 10th, 2021 4:00PM
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.
Cory Boschman,
Watch for increasing hazard as the storms roll in. Especially in wind loaded areas where snow accumulations may be more than forecasted. Also, a reminder of the closures for caribou habitat. Check them out before planning your next adventure.
Summary
Weather Forecast
Monday: Flurries:8 cm. Alpine temp: High -6 °C. Ridge wind southwest: 25 km/h gusting to 75 km/h.
Tuesday: Snow:19 cm. Alpine temp: Low -7 °C, High -4 °C. Ridge wind southwest: 25 km/h gusting to 70 km/h.
Wednesday: Cloudy with sunny periods and isolated flurries:5 cm. Alpine temp: Low -14 °C, High -8 °C. Ridge wind west: 15 km/h gusting to 50 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
Forecast snowfall amounts are uncertain
Problems
Wind Slabs
Ongoing Strong to Extreme SW winds continue to form wind slabs at treeline and above. They appear to be stubborn with only a few natural avalanches observed in the past 4 days, but be vigilant for human triggering.
- If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.
- Use caution in lee areas. Recent wind loading has created reactive slabs.
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.
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
- Avoid thin, rocky or unsupported slopes.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Jan 11th, 2021 4:00PM
