Bulletin d’avalanche

Purcells

Feb 26 – 27, 2014Avalanche Canada
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Archivé · expiré 13 years ago

Danger d’avalanche

Fri
Sat
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué

Points saillants

Recent warm temperatures have added another dimension to the puzzle. Watch out as temperatures climb, especially on solar aspects. For more insight, check out the latest Forecasters Blog.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–4
    The hazard may increase with rising temperatures and solar warming on South aspects. See the forecasters blog for more information on current tricky conditions.
  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible - Likely
    Taille
    2–5
    A thick storm slab from the last series of storms now lies above a touchy, persistent weak layer. This slab has shown a propensity for remote triggering and propagating over wide distances. In wind-loaded areas the slab may be up to 2m thick.

Avalanche Summary

Natural and skier accidental avalanches are still occurring up to size 2  in the forecast area, and as temperatures warm up may increase in frequency. Cornices failures may also occur with the warming temperatures and will certainly add to the hazard.Conditions are ideal for human triggering right now and we have received numerous reports of skier triggered and skier accidental avalanches, many of which have released quite deep in the snowpack. Neighboring areas have reported avalanches that were remotely triggered from a considerable distance. Operators are listing warming temperatures and cornice failures as a considerable hazard.

Snowpack Summary

A cohesive slab with an average thickness of 1.3m sits on a nasty persistent weak layer (surface hoar/facet/crust combo) that was formed during the preceding month of cold, dry weather. This weak layer is widespread at all elevations and aspects, and is creating problems even in previously skied terrain. Large settlements and whumpfs have been reported at all elevations. We have received numerous reports of remotely-triggered avalanches from as far as 500m away which indicates a high likelihood of large propagation within the weak layer. Touchy conditions are expected to remain in place longer than we're normally accustomed to. In many wind loaded areas, a slab of up to 2m thickness overlies the persistent weak layer creating conditions for very large avalanches.Weak basal facets and depth hoar have been noted in reports from some areas, but triggering has now become unlikely. For the most part, the mid and lower snowpack are strong and well consolidated.

Confidence

Fair - Timing or intensity of solar radiation is uncertain

Weather Forecast

The arctic ridge of high pressure dominates conditions for the forecast period. Clear and dry conditions with cold arctic air scheduled to move back into the region. Strong arctic outflow winds have already begun in the north and will move into the south by the coming weekend.Wednesday night:  Freezing level at valley bottom, ridge top winds light-variable.Thursday: Cloudy periods, freezing level around 1800m, ridge top winds, light, gusting to 30Km/h.Friday:  Cloudy with flurries and a trace of precipitation. freezing level at valley bottom, ridge top winds from the North,15-20 Km/hSaturday:  Sunny with cloudy periods, freezing level at valley bottom, light ridge top winds from the SE.

Régions couvertes