Avalanche forecast

South Rockies

Mar 4, 2017Avalanche Canada
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Avalanche danger

Sat
Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

If you see more then 25 cm of new snow overnight then consider the danger rating to be HIGH.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    Reactive storm slabs continue to build and are primed for rider triggering. Thicker and stiffer slabs will exist on leeward slopes due to wind transported snow.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–4
    A weak layer near the base of the snowpack has the potential for large avalanches, especially in areas with minimal rider compaction or thin variable snow cover.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Saturday

Weather Forecast

Friday night: Snow amounts 5-20 cm with strong ridgetop winds. Freezing levels 1000 m.Saturday: Mostly cloudy with sunny periods and isolated flurries. Light winds from the SW, alpine temperatures -7 and freezing levels 1100 m.Sunday: Mostly cloudy with snow amounts 5-10 cm. Moderate winds from the S-SW. Alpine temperatures near -10 and freezing levels valley bottom.Monday: Cloudy with sunny breaks and a trace of new snow. Ridgetop winds strong from the SW. Alpine temperatures near -11.

Avalanche Summary

No new avalanche reports for Friday. On Thursday, a size 2.5 deep persistent slab avalanche was reported from the Elkford- North riding area. It was from approximately 2500 m on a SE aspect. It looked to be 24 hrs old and likely failed earlier in the storm. It did fail within the basal facets (deep persistent slab) and scrubbed down to rocks. Widespread loose dry avalanches were also noted from steep terrain features up to size 1.5. Natural avalanche activity may taper off, however; slab avalanches may be primed for human triggering.

Snowpack Summary

Another 14 cm of low density storm snow arrived overnight bringing the recent snow totals up to 80 cm in the past week. The new snow will likely have a poor bond to previous old snow surfaces that consist of stiff wind slabs, crusts and facets. Strong southwesterly winds is redistributing the new snow onto leeward slopes, building thicker and stiffer slabs. The mid-pack in this region is generally well settled and strong, but the bottom third of the snowpack is composed of weak facets (sugary snow crystals). Approximately 100-120 cm of settled snow sits above the weak layer of sugary, rotten facets that developed mid- December. This remains a concern and should be on your radar, especially with continued forecast snow and strong winds potentially overloading the weakness.

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