Avalanche Forecast
Issued: Nov 30th, 2020 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Deep Persistent Slabs.
JSmith,
Avalanche Canada
Lingering wind slabs may remain surprisingly reactive to human triggers in areas where they are sitting on top of a layer of small surface hoar.
Summary
Confidence
Weather Forecast
MONDAY NIGHT: Clearing skies / Moderate, northwest ridgetop wind / alpine low temperature -14 / Freezing level valley bottom.
TUESDAY: Sunny / Light, northwest ridgetop wind / alpine high temperature -3 / Above freezing layer of air moving in late afternoon and creating a strong temperature inversion with warm air above roughly 2000 m.
WEDNESDAY: Sunny / Light, southwest ridgetop wind / alpine high temperature +1 / Strong inversion with an above freezing layer of air above 2000 m.
THURSDAY: Sunny / Light, southwest ridgetop wind / alpine high temperature +1 / Strong inversion with an above freezing layer of air above 2000 m.
Avalanche Summary
Check out this notable MIN report of numerous human triggered avalanches from Quartz Creek on Saturday. The buried layer of small surface hoar that caused this avalanche could catch riders by surprise.
Data is very sparse in this region. Please submit your observations to the Mountain Information Network.
Snowpack Summary
Around 5 cm of new snow on Monday has covered a layer of surface hoar found primarily at treeline and below. The strong southwest winds from last week created wind slabs on lee features at treeline and above. There were a couple human triggered avalanches on a small layer of buried surface hoar. This layer has been reported as "spotty" and is most likely to be present in sheltered areas. There is a crust from early November that is down approximately 50-75 cm. This layer has been observed to have weak, sugary facets above and below it and is most likely to be reactive to human triggers on south facing slopes and in shallow, rocky, snowpack areas in the alpine..
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- In times of uncertainty conservative terrain choices are our best defense.
- Closely monitor how the new snow is bonding to the old surface.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
Problems
Wind Slabs
Lingering wind slabs may remain surprisingly reactive to human triggers in areas where they are sitting on top of a layer of small surface hoar.
Aspects: North, North East, East, South East, South, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Deep Persistent Slabs
A crust from early November exists down about 50-75 cm. This layer has weak, sugary facets above and below it. This layer is most likely to be reactive to human triggers on south facing slopes and in shallow, rocky, snowpack areas in the alpine.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Dec 1st, 2020 4:00PM
