Avalanche Forecast
Issued: Nov 29th, 2020 8:29AM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Persistent Slabs.
Mike Smallwood,
Widespread wind affect has increased slab cohesion and reduced the travel quality at and above treeline. Expect all areas exposed to wind transport to have more reactive slabs
Summary
Weather Forecast
High pressure continues for today with clear skies, light SW wind and a high of -7. Trace snow will start tonight and continue through the day tomorrow with cloudy skies, a high of -6 and a brief W wind spike in the evening. Tuesday brings a significant high pressure ridge forecast to hold clear skies for the week
Snowpack Summary
60 cm of storm snow sits over old snow and the Nov 23 surface hoar size 3. The surface hoar has been observed, rounding, at treeline in isolated areas but not found in other profiles. The Nov 5 crust is now between 90 and 140cm down which is within the triggerable range for skiers and snowboarders in some areas.
Avalanche Summary
A skier triggered sz 2 from Overlook yesterday had very wide propagation. Numerous natural avalanches sz 1.5 to 2.5 on all aspects in the hwy corridor and Connaught creek yesterday as well 3x sz 3s including Cheops N 4. A skier triggered sz 1.5 in Avalanche Crest and a 2.5 in Quartz this week failed on SH with wide propagation.
Confidence
Problems
Wind Slabs
60cm of snow fell this week with strong SW winds. Slabs will be more reactive in open wind affected areas in the alpine and at treeline. In isolated areas this has been reactive in sheltered areas over a preserved surface hoar layer
- Avoid terrain traps, such as gullies, where the consequences of a small avalanche could be serious.
- Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Persistent Slabs
Steep planar slopes should be avoided, especially at treeline and into the lower alpine. Recent natural/human triggered avalanches, snowpack test and reports of whumphing indicate that this layer may still be triggered by the weight of a skier.
- Avoid shallow snowpack areas where triggering is more likely.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Nov 30th, 2020 8:00AM
