Avalanche Forecast

Issued: Mar 27th, 2021 4:00PM

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

Avalanche Canada kdevine, Avalanche Canada

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Use caution as you transition into wind exposed terrain, new snow combined with southwest wind is expected to promote wind slab development at upper elevations

Summary

Confidence

Moderate - Uncertainty is due to the timing of the incoming weather system.

Weather Forecast

SATURDAY NIGHT - Mainly cloudy / strong southwest wind / alpine low temperature near -2 / freezing level 1600 m

SUNDAY - Flurries, 5-10 cm, with another 10-20 cm overnight / strong southwest wind / alpine high temperature near -2 / freezing level 1800 m

MONDAY - Mainly cloudy with scattered flurries / light to moderate northwest wind / alpine high temperature near -8 

TUESDAY - A mix of sun and cloud / light to moderate west wind / alpine high temperature near -6 / freezing level 1500 m

Avalanche Summary

New snow with strong wind is expected to form fresh and reactive wind slabs in lee terrain on Sunday. Wet loose avalanches are possible at lower elevations if it begins to rain.

There were no new avalanches reported in the region on Friday.

On Thursday, there were a few reports of dry loose avalanches on steep south-facing terrain.

On Wednesday, the neighboring Waterton National Park reported size 1 dry loose activity on steep solar aspects. 

On Monday and Tuesday, we received a few reports of size 1 natural and explosive-triggered wind slabs in steep, unsupported alpine features in the south of the region where recent snowfall amounts have been greatest.

Snowpack Summary

5-10 cm of new snow is expected on Sunday with strong southwest wind. This precipitation may fall as rain below treeline. Fresh and reactive wind slabs will likely be forming in lee terrain in the alpine and open treeline areas. 

The new snow will fall mainly onto wind affected snow and a crust at lower elevations and on solar aspects.

30-60 cm of snow sits above a layer of sugary facets that were buried in mid-February. In some areas, there may be an old layer of feathery surface hoar or facets from late January down 50 to 80 cm deep. There have been no reported avalanches on either of these layers in the region since March 9th in the Crowsnest area.

The mid-pack is firm and well settled. Some faceted snow and a decomposing melt-freeze crust can be found near the base of the snowpack.

Terrain and Travel

  • Fresh wind slabs will likely form throughout the day, diligently watch for changing conditions.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.

Problems

Wind Slabs

An icon showing Wind Slabs

Fresh and reactive wind slabs are expected to build throughout the day with new snow and strong wind.

Aspects: North, North East, East, South East, North West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Mar 28th, 2021 4:00PM