Avalanche Forecast

Issued: Mar 16th, 2017 5:34PM

The alpine rating is considerable, 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.

A momentary reprieve from the precipitation and high freezing levels on Friday. Yet we still have dangerous avalanche conditions. Saturday it will start all over with precipitation and warm temperatures forecast again.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Saturday

Weather Forecast

FRIDAY: Scattered flurries / Moderate south wind / Alpine temperature -6 / Freezing level 1400mSATURDAY: Snow, accumulation 25-30cm / Moderate to strong southwest wind / Alpine temperature -3 / Freezing level 1900mSUNDAY: Broken skies with isolated flurries / moderate west wind / Alpine temperature -11 / Freezing level 800mMore details can be found on the Mountain Weather Forecast.

Avalanche Summary

The past 2 days have seen a widespread natural avalanches to Size 4 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 and running full path. Wet slabs and loose wet avalanches have also been reported below treeline.

Snowpack Summary

Around 60-100cm of new snow has fallen at upper elevations over the past several days and has been redistributed by moderate to strong southerly wind. Warm temperatures on Sunday through Wednesday has resulted in moist and/or rain saturated snow on all aspects up to 2100m. There may now be a weak surface crust found between 1300 and 2100m. The snowpack below approximately 1300m is reported to be isothermic. The new snow sits on top of faceted snow as well as isolated small surface hoar in shelteredTue 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.

The new snow will require several days to settle and stabilize.Be cautious as you transition into wind affected terrain.Watch for signs of instability such as whumpfing, or cracking.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Various persistent weakness throughout the snowpack create the potential for large step-down avalanches. Heavy loads such as a smaller storm/wind slab avalanche or even a cornice failure will increase the likelihood of triggering these layers.

Use conservative route selection, choose moderate angled and supported terrain with low consequence.Be aware of the potential for wide propagations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Loose Wet

As temperatures slowly cool there may still be the lingering possibility of triggering loose wet avalanches that step down to deeper weak layers.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 17th, 2017 2:00PM