Avalanche Forecast

Issued: Feb 16th, 2014 8:06AM

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

Avalanche Canada rbuhler, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

A strong west to southwesterly flow continues to drive a series of moist systems across the interior regions. The next frontal system will cross the interior on Sunday night and most of Monday resulting in more precipitation and wind. This storm is tracking through the south of the Purcells and the areas around Golden may not see as much precipitation from the first system. The second system is expected to affect the entire region Tuesday overnight. Wednesday is expected to be mainly dry with periods of sun.Sun. Night/Monday: Snowfall 10-15cm (less in the north), freezing level rising to 1300m in the afternoon, ridgetop winds 30-50km/h SW easing in the afternoon.Tuesday: Mostly dry during the day, snowfall overnight 8-12cm, freezing level rising to 1300m in the afternoon, ridgetop winds 25-40km/h SW increasing overnight.Wednesday: Mostly dry, a mix of sun and cloud, afternoon freezing level around 500m, ridgetop winds 40-60km/h W-NW easing in the afternoon.

Avalanche Summary

A widespread natural avalanche cycle has been occurring across the forecast area over the last few days with natural and human-triggered avalanches up to size 3. These avalanches are occurring on all aspects and elevation bands.

Snowpack Summary

Snowfall amounts have varied across the forecast region, but up to 100cm+ of storm snow is settling into a cohesive slab which is now typically 50-80cm thick. This slab is sitting on the weak Feb 9 interface which consists of multiple layers of surface hoar, faceted snow, and/or crusts from the past few weeks of cold clear weather. Reports indicate very easy snowpack tests results and widespread large destructive avalanche activity. Due to the persistent nature of these buried weaknesses, touchy conditions are likely to exist for some time.Strong ridge top winds have created wind slabs on leeward features at treeline and above. These wind slabs are the primary concern for the near future and strong forecast winds over the next few days are expected to add to this problem.For the most part, the mid and lower snowpack are strong and well consolidated. However, weak basal facets are likely to exist in some areas but triggering has now become unlikely.

Problems

Storm Slabs

An icon showing Storm Slabs
Snowfall over the last week is settling into a storm slab (typically 50-80cm thick) above the weak Feb.10th surface hoar/facet/crust interface.  Stiffer wind slabs also exist in leeward features in wind exposed areas.
Avoid all avalanche terrain during periods of heavy loading from new snow, wind, or rain.>Use caution in lee areas in the alpine and at treeline. Recent wind loading has created wind slabs.>Choose conservative lines and watch for clues of instability.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 5

Valid until: Feb 17th, 2014 2:00PM

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