Bulletin d’avalanche

Vancouver Island

Apr 5 – 6, 2021VIAC
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Archivé · expiré 5 years ago

Danger d’avalanche

Tue
Wed
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

A few small size 1 skier triggered wind slabs reported on North aspects between 1400 and 1500 meters.

Problèmes avalancheux

  • Wind Slabs

    • Toutes altitudes
    Probabilité
    Possible
    Taille
    1
    Old residual wind slabs exist as well new slabs likely to form during periods of snow fall and moderate to strong south west winds. Location: North East thru to North West aspects and found in both the Alpine and Tree line. Possibility: Triggering of this avalanche problem is possible from light loads such as skiers. Natural avalanches are unlikely. Size: If triggered expect these avalanches to be large size 2.

  • Cornices

    • Toutes altitudes
    Probabilité
    Possible
    Taille
    1
    Cornices are widespread and large. Previous warming and cooling may have added some temporary strength, This problem will persist through the remainder of the season and can be both a trigger for slopes below as well are large enough to create an avalanche hazard alone. Location: Predominantly north aspects at ridge top in the Alpine and Tree line. Possibility: Triggering of this avalanche problem is unlikely to possible from light loads such as skiers/snowmobilers. Natural avalanches are unlikely. Size: If triggered expect these avalanches to be large size 2, on isolated terrain features very large, size 3

  • Loose Wet

    • Toutes altitudes
    Probabilité
    Possible
    Taille
    1
    Clear sky, direct sun effect and warming temps will cause loose wet avalanches to occur on solar aspects. Location: Solar aspects Possibility: Triggering of this avalanche problem is likely to very likely from light loads such as skiers. Natural avalanches are possible to likely. Size: If triggered expect these avalanches to be small size 1, and on isolated terrain features they may be able to gain mass and could be large, up to size 2 .

Past Weather

10-15 cm of snow fell above the 800 meter mark combined with moderate to strong south west wind. In the wake of this small weather disturbance, clear sky and warm temps occurred on Sunday with freezing levels rising to 2000 meters during the later afternoon.

Weather Forecast

A ridge of high pressure will provide clear sky and sunshine for both Monday and Tuesday. Beginning late Tuesday a low pressure system to the north of the area will begin to move south bringing increasing south west wind and precipitation. **Monday:** No new precipitation Winds light from the South West , Freezing levels at sea level rising during the daytime to 1600 meters. Temps at 1500 meters up to 1 degrees.**Tuesday:** Trace amounts of snow, Winds light to moderate from the South West, Freezing levels 1000 meters. Temps at 1500 meters -3 degrees.**Wednesday:** 15 to 20 cm of snow , Winds moderate to strong from the South West, Freezing levels 900 meters. Temps at 1500 meters - 4 degrees.

Terrain Advice

Caution when transitioning into freshly wind loaded slopes.Avoid travelling both above and below cornices.Avoid solar aspect during periods of clear sky, warming and when snow surfaces become moist and unconsolidated.

Snowpack Summary

The upper snowpack surfaces consists of some wind loaded pillows on north aspects with south aspects seeing direct sun and warming followed by overnight cooling forming a crust that is supportive to skis. Two crust exist in the upper snowpack one at 30cms and the other at 100cms. Both of these crusts are producing results in the moderate to hard range and are currently not concerning as they are well bridged and protected from the dense layer above. However, expect these layers to produce results/ avalanches during a prolonged period of warmth or a large increase in load such as 30 to 100mm of water. Mid and lower snowpack is well settled and dense. Overall snowpack average depths range from 300cm to 600cm and are dependent on elevation and range location.

Snowpack Details

  • Surface: Variable surface conditions, dependent of elevation and orientation.
  • Upper: Two reactive melt freeze crusts exist at 30cm and 100cm.
  • Mid: Well settled and dense.
  • Lower: Well settled and dense.

Confidence

Moderate - Numerous field observations and good agreement between forecasts weather models for this area.

Régions couvertes