Avalanche forecast

Northwest Inland

Mar 16 – 17, 2016Avalanche Canada
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Avalanche danger

Fri
Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Strong sunshine will increase avalanche danger during the day. Plan your route to minimize exposure to big sun-drenched slopes in the afternoon.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–4
    Variable and shifting winds may have created fresh wind slabs on a variety of aspects in exposed terrain. Sun and warming could increase the sensitivity of triggering this problem. 

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–5
    Cornices are reported to be large and weak. Natural cornice releases are possible with sun exposure and warming.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    3–6
    Three buried weaknesses remain a concern, mainly in the north of the region (see snowpack discussion for details). Isolated very large avalanches remain a possibility, especially with a heavy trigger like a falling cornice.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

THURSDAY: Mainly sunny. The freezing level is around 1000-1200 m. Ridge winds are generally light: A mix of sun and cloud. The freezing level should jump to around 1400-1600 m and ridge winds are light to moderate from the E-SE. SATURDAY: Increasing cloud. The freezing level is around 1500 m and winds should be light.

Avalanche Summary

Wind-loaded N-E facing alpine slopes were reactive skier triggering with wind slabs up to size 1.5 in parts of the region on Tuesday. On Monday, a natural cornice release triggered a size 1.5 wind slab on a northwest aspect at 1750m which was 25cm thick. Skiers were triggering size 1 soft slabs on steep leeward slopes. In the far north of the region, a natural cornice release triggered a size 2.5 slab which released on the early March surface hoar layer.

Snowpack Summary

In sheltered areas at higher elevations, 20-30cm of low density snow can be found. Recent southerly winds have redistributed the surface snow in exposed terrain formed wind slabs and cornices in leeward terrain. South facing slopes could be capped a sun crust or moist snow depending on the time of day. A layer of surface hoar from early March can be found down 60-80cm but only seems to be a problem for the northern half of the region. Professional operators are still tracking two deep weak layers from early-January and early-February which can be found down about 1m or more. These layers have been dormant for a couple weeks but could wake up with heavy storm loading, substantial warming, or a heavy trigger like a cornice fall. In the far north of the region, there is an isolated weakness at the base of the snowpack that has been responsible for some very large and destructive avalanches.

Regions covered