Avalanche forecast

South Rockies

Feb 6, 2017Avalanche Canada
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Avalanche danger

Mon
Tue
Alpine
5 · Extreme
Treeline
5 · Extreme
Below
4 · High
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Highlights

AVOID ALL AVALANCHE TERRAIN. It's time to rein in your terrain choices to simple, no consequence areas. Better yet, stick to the ski hill. Avoid all overhead hazard as well - avalanches have the potential to run to valley bottom.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–3
    Very touchy storm slabs have formed on virtually all aspects and elevations, especially in the alpine and tree line areas. Avoid all avalanche terrain and overhead exposure.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3
    Triggering deeper weak layers remains possible where hard slabs sit above weak sugary snow. This is most likely in thin snowpack parts of the region.

Confidence

Moderate - Intensity of incoming weather systems is uncertain

Weather Forecast

Significant heavy snowfall (especially in the southern areas) right through Monday afternoon with moderate southwesterly winds. MONDAY: Heavy snow Sunday overnight into Monday with 35-80cms forecast / Moderate southwest wind / Alpine temperature -12TUESDAY: Scattered flurries / Light southwest wind / Alpine temperature -10WEDNESDAY: Periods of snow, accumulation 5-10cm by day's end / Light to moderate southwast wind / Alpine temperature -8

Avalanche Summary

Soft slabs from the storm snow (to Size 1.5) were very reactive to ski cutting and explosives control on Saturday. The size and distribution of avalanches will increase significantly by Monday afternoon: It's time to seriously dial back the terrain use and stick to simple, no consequence terrain. The possibility of triggering the weak faceted layers deeper in the snowpack remains a concern, and storm slabs may step down to trigger larger, more destructive avalanches. .

Snowpack Summary

Storm snow totals are taking on epic proportions near Castle mountain with upwards of 60cm falling in the past two days. Across the region, 25-60cm of new snow typically sits on wind-affected surfaces at higher elevations. This new snow is forming touchy soft slabs on all aspects in the alpine and treeline as winds were shifting on Saturday. Below 1500 metres you may find an isolated thin breakable rain crust about 1 cm thick. The snowpack is quite variable throughout the region. In deeper areas, the snowpack appears to be well settled with isolated concerns about the mid-December facet layer buried 50-100 cm deep. In shallow snowpack areas and lower elevations, the snowpack is weak and faceted. For instance, in the Elk Valley north area near Crown Mountain last week the height of snow was 90 cm with foot penetration of 80 cm; or almost to ground. In these areas, the wind has formed isolated hard slabs above weak facets and created the potential for large persistent slab avalanches.

Regions covered