Bulletin d’avalanche

Purcells

Jan 2 – 3, 2014Avalanche Canada
Voir sur la carte
Archivé · expiré 13 years ago

Danger d’avalanche

Sat
Sun
Alpin
4 · Fort
Limite forestière
4 · Fort
Sous la limite
3 · Marqué

Points saillants

A number of significant avalanches have occurred in the north of this region and just beyond its northern boundary. Check the forecaster blog. Use caution if traveling in the backcountry at this time.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–5
    A weak layer buried around 50 cm has become reactive and can be readily triggered, especially at higher elevations on a variety of aspects.
  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Very Likely
    Taille
    1–4
    New storm snow has been poorly bonding to the existing snowpack. Forecast new snow and winds will increase the likelihood of triggering an avalanche.
  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    2–6
    The most likely place to trigger a deeper layer is on a steep, convex, north-facing slope in an area with a relatively shallow snowpack.

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain on Thursday

Weather Forecast

Storm totals should be in the 10-25cm range with the most intense precipitation occurring on Thursday night. The freezing level drops after the storm and a ridge of high pressure looks to dominate for the foreseeable future.Thursday Night: Freezing Level: 1000m; Precip 5/15mm 5/20cmFriday: Freezing Level: 900m; Precip: 2/5mm 2/10cm; Wind: Mod NWSaturday: Freezing Level: Valley Bottom; Precip: Nil; Wind: Mod, NW Sunday: Freezing Level: Valley Bottom; Precip: Nil; Wind: Light, Var.(Forecasted wind speeds are at 2000m)

Avalanche Summary

A number of significant avalanches have been reported from the north of this region and just beyond its boundary to the north. One very large (size 3) avalanche was reported on Tuesday on a N aspect at 2200 m from relatively gentle terrain with a fracture depth of 100 cm. Two large (size 2) avalanches were reported from near Golden on Monday, likely triggering buried surface hoar from 10-Dec down around 50 cm. A size 3 natural avalanche was reported from the Bugaboos on Sunday on a NE aspect at 2650m, triggered by a cornice release that pulled out a large slab all the way to ground on the slope below. Outside the boundary of this region to the north of Golden, there was an incident in the Hope Creek drainage, where four people were involved (with two sustaining injuries) in a size 3 avalanche in an alpine feature on a NE aspect. Avalanche activity on Wednesday was limited to small wind slabs.

Snowpack Summary

Up to 25 cm of recent storm snow has been redistributed by moderate to strong northwest and southwest winds. In the upper metre of the snowpack a couple of persistent weak layers exist. The upper one comprises surface hoar and is buried around 40-50 cm. The lower one comprises a facet/crust combo and is buried 80-100 cm. Both interfaces give variable results with snowpack tests, but professional operators are treating them with caution.A bigger concern, especially in the Northern part of the region is a layer of weak sugary depth hoar crystals at the base of the snowpack that lie above a crust from early October. Several large avalanches in the last 10 days have been attributed to failures at this layer. Wide propagations on relatively gentle terrain have been noted, as well as a tendency for seemingly disconnected slopes to become connected by one large avalanche.

Régions couvertes