Avalanche Forecast

Issued: Feb 13th, 2021 3:00PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Wind Slabs and Persistent Slabs.

Avalanche Canada jcoulter, Avalanche Canada

Shifting wind direction and potential for new snow will keep danger elevated on Sunday. There may be potential for wide propagation on bigger terrain features.

Summary

Confidence

Moderate -

Weather Forecast

SATURDAY NIGHT- Overcast, 2-5 cm, moderate to strong south west wind / low near -10

SUNDAY - Overcast, 5-15 cm, strong south west wind, highs near -9

MONDAY - Cloudy, flurries, moderate to strong west wind, -8

TUESDAY- Cloudy, trace snow amounts, moderate north west wind, high near -5

Avalanche Summary

In the Terrace vicinity, recent natural wind slabs to size 2 have been reported on various wind loaded and cross loaded aspects. Wind slabs were also reactive to human triggering with ski cuts in the size 1-1.5 range.

On Friday in the far north and in the south of the region, a few natural size 3 avalanches from big features occurred.

On Tuesday wind slabs up to size 2 were reported by various operators. The northern part of the region had the biggest reported events with windslabs up to size 2.5 on the late January interface.

On Monday, skiers were able trigger unsupported pillows failing on surface hoar down 25-40 cm near Terrace.  

Snowpack Summary

Outflow winds have built wind slabs (where snow is just not sublimating) and reverse loading features. Hard slabs, scoured slopes and sastrugi will be present where outflow effects were the strongest. In more sheltered zones, reactive wind slabs will be found on a variety of aspects and elevations due to terrain effects and the variable wind directions.

Cold temperatures are encouraging surface faceting of the upper snowpack. The late January interface is down 30-70 cm, this consists of surface hoar in sheltered locations, a crust on solar features, and facets and stiff wind affected snow at upper elevations. Below treeline, 10-30 cm of snow sits above isolated pockets of surface hoar and a crust that is more prominent on solar aspects. 

The mid-pack seems to be well settled. Deep persistent layers appear to have mostly become unreactive, with the exception of the Bear Pass area and the far reaches south of Kitimat. 

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Potential for wide propagation exists, fresh slabs may rest on surface hoar, facets and/or crust.

Problems

Wind Slabs

An icon showing Wind Slabs

Steep, lee westerly aspects have been the most reactive during the strong outflow winds. With winds shifting again to westerlies and potential new snow, expect reactive wind slabs on multiple aspects and elevations. Wind slabs will be especially susceptible to human triggering where stiff and punchy feeling snow sits on top of weak faceted crystals. Note that in some places avalanche hazard may be elevated where winds have penetrated into open pockets of terrain even at lower elevations.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs

30-70 cm sits above a buried weak interface that consists of surface hoar, facets, and/ or a crust. As the snow above this layer becomes more consolidated, the likelihood of avalanches may increase. Wind slabs may also cause step down avalanches on this layer.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Feb 14th, 2021 4:00PM