Avalanche forecast

Purcells

Feb 15 – 16, 2016Avalanche Canada
View on map
Archived · expired 11 years ago

Avalanche danger

Wed
Thu
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
Open full map

Highlights

A recent size 3 persistent slab avalanche near Golden is a clear indication that deeply buried weaknesses cannot be trusted. Extra caution is required in the north of the region near Golden.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–3
    New wind slabs are expected to form on Monday night in response to light amounts of new snow and wind. Watch for triggering in the lee of ridgecrests at treeline and in the alpine.

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3–5
    A recent size 3 persistent slab avalanche near Golden is a clear indication that deeply buried weaknesses cannot be trusted. Extra caution is required in the north of the region near Golden.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2
    Recent storm accumulations may react as a loose wet avalanche in steep, sun-exposed terrain.  Warming may also trigger destructive cornice falls. Be extra cautious if the sun makes an appearance on Tuesday.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Monday

Weather Forecast

TONIGHT: 5-10cm of snow / Strong southwest winds / Freezing level at 1500m  TUESDAY: Mix of sun and cloud / Light to moderate southwest winds / Freezing level at 1800m  WEDNESDAY: Light flurries / Light to moderate southwest winds / Freezing level at 1800m  THURSDAY: 5-15cm of snow / Moderate southwest winds / Freezing level at 1500m

Avalanche Summary

On Monday naturally triggered wind slabs to size 2 were observed in the Golden area. On the same day, a size 3 naturally triggered persistent slab avalanche was also noted in Canyon Creek (Golden Backcountry). The avalanche is thought to have been triggering by a wind slab in motion stepping down to the early January persistent weak layer. Increasing southwest winds and new snow on Monday night will spark a new round of wind slab activity in higher elevation lee terrain. Periods of sun on Tuesday may also promote loose wet avalanche activity in steep sun-exposed terrain, especially in spots where new snow is exposed to solar radiation for the first time.

Snowpack Summary

On Monday night, generally light amounts of new snow are expected to fall, and strong southwest winds are expected to form new wind slabs in lee features at treeline and in the alpine. The new snow will overlie wind slabs which formed over the past few days. About 15-40 cm below the surface, you'll likely find a melt freeze crust which exists in most places except for in high elevation shaded terrain. In general there seems to be a reasonable bond between the crust and the overlying snow. I'd still keep an eye on this interface as it has become reactive on some features. The early January surface hoar/ facet layer is typically down 70-120 cm. Sporadic yet destructive avalanche activity continues on this persistent weak layer. In general, the lower snowpack is well settled and strong, apart from some thin snowpack areas where basal facets exist.

Regions covered