Bollettino valanghe

Purcells

Nov 29 – 30, 2020Avalanche Canada
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Archiviato · scaduto 6 years ago

Pericolo valanghe

Tue
Wed
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole

In sintesi

 Recent strong southwest winds have created fresh wind slabs on lee features at treeline and above. These wind slabs may be surprisingly reactive in areas where they are sitting on a spotty layer of small surface hoar.  

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Recent strong southwest winds have created fresh wind slabs on lee features at treeline and above. These wind slabs may be surprisingly reactive in areas where they are sitting on a layer of small surface hoar.    

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    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.

Confidence

Low - Uncertainty is due to the limited number of field observations.

Weather Forecast

SATURDAY NIGHT: Clear / Light, west wind / alpine low temperature -13 / Freezing level valley bottom.

 SUNDAY: Mostly sunny / Light, west wind / alpine high temperature -6 / Freezing level valley bottom.

MONDAY: Cloudy with flurries; 0-3 cm. / Light to moderate, west wind / alpine high temperature -7 / Freezing level valley bottom.

TUESDAY: Mostly sunny / Light, west wind / alpine high temperature -9 / Freezing level valley bottom.

Avalanche Summary

Check out this notable skier triggered avalanche from Quartz Creek on Thursday. The recently buried layer of small surface hoar that caused this avalanche could likely catch riders by surprise this weekend!

In the past week there have been a few size 2 avalanches reported on the early November crust. These have been triggered by both humans and explosives.

If you get out into the mountains, please consider sharing your observations on the Mountain Information Network!

Snowpack Summary

  Recent strong southwest winds have created fresh wind slabs on lee features at treeline and above. There have been a couple human triggered avalanches on a recently buried layer of small 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.

Regioni coperte