Avalanche forecast

Lizard-Flathead

Mar 23 – 24, 2017Avalanche Canada
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Archived · expired 10 years ago

Avalanche danger

Sat
Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low

Highlights

Wind and snow will build fresh wind slabs throughout the day. Avoid lingering in the runout of avalanche paths because a cornice fall could trigger a large avalanche.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–2
    Strong winds will be forming fresh wind slabs throughout the day in the lee of exposed terrain.
  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    Heavy triggers such as a cornice fall or wind loading are potential triggers for large avalanches on deep weak layers. Stay aware of overhead hazard when traveling at lower elevations.

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

FRIDAY: Increasing cloud and afternoon flurries with about 5 cm, strong southwest wind, freezing level around 1600 m with alpine temperature around -3 C.SATURDAY: Overnight snow with another 10 cm easing and clearing throughout the day, strong southwest wind, alpine temperature around -5 C.SUNDAY: Mostly sunny, moderate southwest wind, alpine temperature around -5 C.

Avalanche Summary

On Thursday, a few small storm slabs were reported to run naturally overnight in steep alpine terrain and then also react to explosives in the morning (size 1-1.5). More evidence of large deep persistent slab avalanches from last weekend's avalanche cycle were also reported from the Barnes Lake and Cold Feet areas.Expect wind slabs to develop throughout the day on Friday as another pulse of snow and wind arrives in the afternoon. However, the primary concern is the potential for deep persistent slab avalanches triggered by natural triggers such as a cornice fall. See the forecaster blog for advice on managing a low probability - high consequence problem (here) and the accompanying photos (here).

Snowpack Summary

Light precipitation has delivered 15-25 cm of heavy snow at higher elevations, while rain soaked has the snow below about 1800 m. The new snow has fallen on a thick rain crust that has capped the snowpack at all elevations. Daytime warming and sunlight tend to break down the crust in some areas, but it remains frozen on northerly alpine terrain. Isolated basal facets exist in shallow snowpack areas and still have the potential to produce destructive full-depth avalanches.

Regions covered