Avalanche Forecast

Issued: Mar 1st, 2023 4:00PM

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

Avalanche Canada JMackenzie, Avalanche Canada

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Intense wind transport is leading to fresh and sensitive wind slabs. Choose low angle terrain, and avoid overhead hazard.

Summary

Confidence

Moderate

Avalanche Summary

A couple of new naturally triggered avalanches were observed in the Goat Range Wednesday afternoon. These were size 2, approximately 100cm deep, but did not propagate widely. The avalanches occurred in steep Alpine terrain on an east aspect, and one of them was possibly triggered by a cornice failure.

Snowpack Summary

Up to 25cm of recent storm snow gave excellent skiing Wednesday, but unfortunately the wind increased to strong from the North by the end of the day and was disturbing the snow. The wind is forecasted to shift to the SW on Thursday. Intense wind transport was occurring at Treeline and above, and it is highly likely that touchy wind slabs are forming at these elevations. Today field teams found easy shears down 25cm, and these shears will only get worse with the increased winds. There are also moderate shears down 30 to 50cm on various versions of old wind slab interfaces. The midpack is strong in deeper snowpack regions near the divide, but the basal facets/depth hoar persist. An avalanche initiated in the upper snowpack could easily step down to the deep persistent weak layers, causing a very large avalanche.

Weather Summary

Thursday will be quite wintery! Temperatures will stay between -13 and -15 all day with SW winds up to 100km/h. Snowfall amounts should reach 10cm by the end of Thursday with a further 2 to 4cm by Friday.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Be aware of the potential for surprisingly large avalanches due to deeply buried weak layers.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Wind Slabs

An icon showing Wind Slabs

Extensive current and forecasted wind transport is creating fresh wind slabs (wind is shifting from the North to the SW overnight). In addition, there are several iterations of buried wind slabs formed in previous wind events down 30 to 50cm in the snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The alpine is still variable in total amounts of snow but the basal layers haven't changed. The entire lower half is either facets, or depth hoar.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3.5

Valid until: Mar 2nd, 2023 4:00PM

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