Bollettino valanghe

South Rockies

Apr 5 – 6, 2021Avalanche Canada
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Archiviato · scaduto 5 years ago

Pericolo valanghe

Wed
Thu
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole

In sintesi

Watch for cornices and wind slabs near ridgetops and be cautious on sun-exposed slopes.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely - Possible
    Dimensione
    1–2

    Small wind slabs may lurk on slippery crusts on lee features below alpine ridgetops, formed by recent convective flurries and southwesterly winds.

  • Cornices

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1.5–2.5

    Cornices are large and looming along many ridgelines. They are capable of triggering large avalanches when they fail.

Confidence

Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack.

Weather Forecast

MONDAY NIGHT: Clear, light northwest wind, treeline temperatures below -6 C with freezing level dropping to valley bottom.

TUESDAY: Sunny, southwest wind increasing to moderate through the day, treeline temperatures reach +4 C with freezing level climbing to 2200 m.

WEDNESDAY: Increasing cloud and some light afternoon flurries, moderate to strong southwest wind, treeline temperatures reach +3 C with freezing level around 2000 m.

THURSDAY: Snow, 5-20 cm, decreasing southwesterly wind, treeline temperatures below -6 C with freezing level dropping below 1000 m.

Avalanche Summary

The last reported avalanche activity was on Thursday when some small wet loose avalanches were observed on steep sun-exposed slopes.

Snowpack Summary

Sunny alpine slopes turned moist on Monday afternoon, 5-15 recent dry snow persists at upper elevations and in shady and north-facing terrain. Some small wind slabs may be found on lee features below alpine ridgetops. Cornices are large, looming, and capable of triggering avalanches when they fail.

The mid-pack is firm and well settled. Some faceted snow and a decomposing melt-freeze crust can be found near the base of the snowpack. 

Glide cracks releasing as full depth glide slab avalanches become more common in the spring and are extremely difficult to predict. Best practice is to avoid slopes with glide cracks.

Terrain and Travel

  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Carefully evaluate steep lines for wind slabs.
  • Be alert to conditions that change with elevation and sun exposure.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.

Regioni coperte