Lawinenlagebericht

Purcells

Dec 15 – 16, 2011Avalanche Canada
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Archiviert · abgelaufen 15 years ago

Lawinengefahr

Sat
Sun
Hochgebirge
2 · Mässig
Waldgrenze
2 · Mässig
Unterhalb
1 · Gering
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Lawinenprobleme

  • Wind Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely - Possible
    Größe
    1–3
    This problem is changing from old wind slab on a non-persistent layer, to new soft wind slab on a recently buried surface hoar and/or crust layer. Remember that old wind slabs exist, and that new more touchy wind slabs are developing.

  • Persistent Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Unlikely - Possible
    Größe
    2–5
    The weak facetted layer near the ground may still be triggered in shallow snowpack areas with the common trigger points being convexities, rocks or clumps of small trees.

Confidence

Fair - Forecast snowfall amounts are uncertain on Friday

Weather Forecast

A few cms (3-5) are forecast for overnight Thursday into Friday. The wind is expected to be light from the west on Friday with temps around -5.0 C at treeline and freezing levels about valley bottom. We may see broken skies during the day on Friday as a bit of a ridge moves through before the next wave of snow starts Friday afternoon. It looks like me may get up to 15 cms by Saturday morning. Moderate to strong winds from the southwest are forecast during this storm. The bulk of the moisture is expected to be a bit North of Revelstoke. A series of Pacific disturbances should continue for the next few days, timing and snow amounts are a bit unsure at this time.

Avalanche Summary

A couple of new explosive released avalanches up to size 2.0 along the highway corridor. No new avalanches reported.

Snowpack Summary

Not much change yet in the Purcells, 5-10 cms of snow across he region in the past few days. This overlies surface hoar, surface facets, old windslabs and sun crusts (on steep south through west aspects). Winds have been sporadic in this period, creating isolated new soft slabs in immediate lee locations. Moving forward, the avalanche danger will increase as the load increases (either by new snow or wind). Be locally aware of changes and if obvious signs of instability are present (cracking, whumphing, recent activity on adjacent slopes) or rapid loading is taking place (heavy snowfall or strong winds) then scale down your terrain choices accordingly. Snow depths are quite variable through the region with 130-150cm in the alpine. There is still concern for triggering the weak basal facets/depth hoar, as these layers have shown sudden collapse results in stability test in shallow areas.

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