Avalanche Forecast

Issued: Mar 15th, 2017 5:21PM

The alpine rating is high, the treeline rating is considerable, and the below treeline rating is considerable. Known problems include Storm Slabs, Persistent Slabs and Loose Wet.

mbender, Avalanche Canada

South Columbia.

Continued precipitation Wednesday night into Thursday combined with moderate to strong southerly winds and the potential for the sun to come out on Thursday will continue to keep avalanche danger ratings elevated.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Thursday

Weather Forecast

THURSDAY: Cloudy with scattered flurries / Moderate to strong southwest wind / Alpine temperature -7 / Freezing level: 1000mFRIDAY: Mix of sun and cloud scattered flurries / Moderate south wind / Alpine temperature -4 / Freezing level 1300mSATURDAY: Flurries, accumulation 15-20cm / Moderate to strong southwest wind / Alpine temperature -3 / Freezing level 1800mMore details can be found on the Mountain Weather Forecast.

Avalanche Summary

The past 3 days have seen a widespread natural avalanches to Size 3 at all elevations and on all aspects. Many of these triggered in the storm snow with some also stepping down to persistent weaknesses deeper in the snowpack. Wet slabs and loose wet avalanches have also been reported below treeline.

Snowpack Summary

Around 60-90cm of new snow has fallen at upper elevations over the past several days and has been redistributed by light to moderate southerly wind. Warm temperatures on Sunday through Tuesday has resulted in moist and/or wet surface snow on all aspects up to 2100m. The new snow sits on top of faceted snow as well as isolated small surface hoar in sheltered areas and a thin sun crust on steep southerly aspects. The persistent weakness buried late-February is now down 80-140 cm, and is composed of weak facetted crystals on a thick rain crust as high as about 1800m and facets on sun crust on steep southerly aspects. The mid and lower snowpack are well settled and stable in deeper snowpack areas, but may be weak and faceted in shallow areas.

Problems

Storm Slabs

Weaknesses within the recent storm snow are susceptible to human triggering. These storm slabs are particularly deep and touchy on slopes loaded by southerly winds and have the potential to step down to deeper buried weak layers.

Be alert to conditions that change with elevation.The new snow will require several days to settle and stabilize.Minimize overhead exposure during periods of heavy loading from new snow, wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

Various persistent weaknesses strewn throughout the snowpack create the potential for large step-down avalanches. Warming is expected to increase the likelihood of these large avalanches, especially with cornice-fall triggers.

Watch for whumpfing, hollow sounds, and shooting cracks.Be aware of the potential for wide propagations.Use conservative route selection, choose moderate angled and supported terrain with low consequence.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Loose Wet

Rain below 2000m has made the surface snow wet. As temperatures slowly cool there may still be the lingering possibility of triggering loose wet avalanches that step down to deeper weak layers.

Be cautious particularly where the debris flows into terrain traps.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 16th, 2017 2:00PM