Avalanche forecast

South Coast Inland

Feb 16, 2017Avalanche Canada
View on map
Archived · expired 10 years ago

Avalanche danger

Thu
Fri
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
Open full map

Highlights

We're into a period of HIGH danger with rapid loading of the snowpack on Wednesday into Thursday: rain to treeline and heavy snow in the alpine.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–4
    This problem is more prevalent in the far north areas of the region and is a low likelihood, high consequence scenario that will need to be monitored as snow loads or temperatures increase.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    The warming trend, strong winds and heavy precipitation will make storm and wind slab avalanches likely in the alpine.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Heavy rain at treeline and below (especially in the south) will cause the snow to become soft and cohesionless. Avoid getting pushed into terrain features like gullies and cliffs, where even small slides could have large consequences.

Confidence

Moderate - Due to the number of field observations

Weather Forecast

Warm and wet still on Thursday. Cooling with isolated flurries on Friday, and improving for Saturday. THURSDAY: Rain or wet snow (25-40 mm / cm) with even higher amounts possible for the Coquihalla / Moderate to strong southerly winds in the afternoon / Freezing level around 1600 m. FRIDAY: Mostly cloudy with locally heavy flurries possible (5-15cm) / High temperatures to -1 Celsius / Light westerly winds / Freezing level around 1200 m. SATURDAY: Cloudy with sunny periods / Ridge winds light southerly / Freezing level around 900m / High temperatures to -2 Celsius.

Avalanche Summary

Limited observations during this storm.In the Duffey Lake zone a Size 2.5 deep persistent slab was reported running on a south-southwesterly aspect near 2200m, likely triggered by solar warming on Monday or Tuesday.

Snowpack Summary

In the Duffey Lake area 25 cm of snow fell on Tuesday in to Wednesday. In the south (Coquihalla) we had moderate southerly winds and heavy rain above 1600m on Tuesday night (and rain to 2000m during the day Wednesday). This new rain (or snow higher up) sits on either wind slabs in the alpine or temperature crusts at treeline and below, especially on east and south aspects. Both of these surfaces will be good sliding layers for future snowfall. The mid-December facets down 130-160 cm still remain a concern especially in shallower snowpack areas in the Duffey, Hurley and/ or South Chilcotins. These deeper weaknesses warrant monitoring, especially with the warming and extra loading this week. In southern areas (Coquihalla), the lower snowpack is reportedly well settled (stronger), than it is to the north.

Regions covered