Avalanche forecast

South Rockies

Feb 25 – 26, 2014Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Don't let the good weather lure you into high risk scenarios. Conditions remain tricky.With clear, sunny skies the avalanche danger can rise quickly.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–4
    Wind has transported snow and built fresh, touchy wind slabs on the leeward side of terrain features. Be aware of weak cornices looming over slopes. If they fail, it could trigger large slab avalanche on the slope below.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    3–6
    The persistent weak layer continues to be very sensitive to any additional load. Remote triggering from adjacent terrain and very long fracture propagations are a major concern on all aspects and elevations.

Confidence

Fair - Timing or intensity of solar radiation is uncertain on Wednesday

Weather Forecast

The arctic ridge of high pressure that has been dominating the Interior Regions will start to retreat on Wednesday, bringing warmer alpine temperatures and slightly rising freezing levels. Some disturbances in this flow will bring cloudy skies and light snow later in the forecast period.Wednesday: Sunny and -2.0 degrees expected in the alpine. Ridgetop winds will be light from the NW. Thursday: Cloudy with light snow and -1.0 degrees in the alpine. Ridgetop winds 25 km/hr from the NW. Freezing levels near 1800 m.Friday: Cloudy with isolated flurries. Alpine temperatures -19.0 and ridgetop winds will be light from the NE.

Avalanche Summary

A few loose dry avalanches from steeper terrain were reported on Tuesday. On Saturday, we received a report of a size 3 snowmobile triggered avalanche in the Coal Creek area (Notch). To our knowledge, there were 7 people involved and all were self rescued. The avalanche was on a North aspect and the crown depth was 1-2 m deep. Conditions remain ripe for human triggers.Natural avalanche activity, especially on steep solar aspects  will likely spike with full sunshine during the forecast period.Check out the South Rockies Blog for recent photos and insights of what people are seeing out there.

Snowpack Summary

Large cornices loom on ridgelines and threaten the slopes below. Variable winds have transported some of the recent storm snow, building new wind slabs on leeward slopes. A persistent slab 80-120 cm thick sits on a weak interface comprising of facets and a crust. It continues to show sudden planar shears at the interface, and a high degree of sensitivity to rider triggers. Wide propagations and remote triggering remain a concern. With forecast sunny periods, solar aspects may see moist snow surfaces which will then form a crust overnight. The deep persistent layer of facets and depth hoar near the base of the snowpack has remained dormant to this point, but may become a concern with additional load and stress on the snowpack like a cornice fall or large avalanche.

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