Bollettino valanghe

Cariboos

Dec 16 – 17, 2011Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 15 years ago

Pericolo valanghe

Sun
Mon
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
Apri la mappa completa

In sintesi

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Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely - Very Likely
    Dimensione
    2–5
    Expect windslab development on lee and cross-loaded features. Anticipate loading lower on the slope with forecast high winds. These windslabs may be sliding easily on the recently buried surface hoar.

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    3–6
    Variable snow depths may make it possible to trigger a deeper instability on steep, unsupported terrain features. Areas that get more new snow may have enough load to make this layer active again.

  • Storm Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–4
    The new storm snow may settle into a cohesive slab that could be touchy to human triggers. Warm temperatures may cause a natural cycle on Saturday.

Confidence

Fair - Freezing levels are uncertain on Saturday

Weather Forecast

The snow is expected to intensify Friday evening. The pacific system is angled a bit to the north of Revelstoke. The North Monashees and the Cariboos should see close to 30 cm by Saturday morning. The Selkirks and South Monashees will probably see closer to 20 cm. Further south should see lesser amounts. Strong winds 60 km/hr with gusts to 80 km/hr are forecast from the southwest on Friday night and Saturday. Some models are showing high freezing levels for Saturday, possibly up to 2000 metres. I think that it is more likely that the freezing level will reach to about 1600 metres in the southwestern ranges, and to about 1200 metres in the north and east ranges. Sunday is forecast to be cooler and drier. Expect flurries and light snowfall in most areas of the interior. The timing of the next system is difficult at this time, but we should see some more snow on Monday or Monday night.

Avalanche Summary

No new avalanches reported. Expect conditions in this region to change overnight resulting in rising danger levels.

Snowpack Summary

The new snow load is building faster in the northern ranges of the interior than it is in the southern and eastern ranges. The depth of the new storm snow above the various old surfaces is what is driving the danger ratings at this time. Large surface hoar and near surface facets are widespread above various crusts and hard wind slabs. Some areas have a sun crust in the alpine on steep south and west aspects. There is a rain crust that is buried between 40-55 cm in some areas that reaches up to about 2200 metres. The mid-pack is reported as generally strong and well settled. Observers are still able to find the early November surface hoar layer. This layer has not been reactive during the recent long dry spell. Tests show that it is getting harder to pull the snowpack apart at this interface. We may still see this layer become active again if we get the right combination of load and warm temperatures. Going down deeper, we still need to consider the interface between the snow that did not melt over the summer, the glacial ice, and the October rain event. If this deeply buried beast wakes up, we may see very large avalanches in high alpine north and northeast aspects.

Regioni coperte