Avalanche Forecast

Issued: Mar 17th, 2023 4:00PM

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

Avalanche Canada GL, Avalanche Canada

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The region is trending towards spring like conditions. Start early and finish early as the sun is having the strongest effect typically by mid-afternoon. It is wise to choose ice climbs with no overhead hazard and least amount of overall sun exposure.

Summary

Confidence

Moderate

Avalanche Summary

Friday's Maligne patrol did not observe anything significant yet this was completed by noon. The afternoon heat may have triggered some slopes after the fact. From March 14-16, the Icefields parkway had numerous medium to large avalanches in the alpine on steep rocky features. Some were cornice triggered and size 3. Small loose wet avalanches were noted in steep solar terrain.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

15-20cm of new snow from March 13th, with moderate SW winds added to the existing windslab in the immediate lee aspects. The new snow is over a sun crust at low elevations steep southerly slopes and old surface facets in sheltered terrain. The mid-pack is 20 to 40cm of low density facetted snow. The lower snowpack is generally weak with large facets and depth hoar at the base. Snowpack depth varies from 60 to 170cm.

Weather Summary

Saturday will bring clouds with sunny periods, -5 °C, light winds, and 1600 metres freezing level. Sunday will be similar but with 1900 metres freezing level. Expect clouds on Monday, similar temperatures, light winds, and 1700 metres freezing level.

Detailed weather forecasts from Avalanche Canada: https://www.avalanche.ca/weather/forecast

Terrain and Travel Advice

  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • It’s possible for avalanche danger to remain elevated into the early evening hours.

Problems

Loose Wet

An icon showing Loose Wet

Loose snow avalanches will be vary from wet to dry depending on aspect and elevation. If the terrain is steep and protected from wind, a loose snow avalanche is possible. Even these smaller avalanches may trigger the deep persistent slab in isolated spots.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 1.5

Wind Slabs

An icon showing Wind Slabs

March 13th 20cm of storm snow accompanied by moderate southwest winds has created wind slabs in the alpine and on isolated features at tree line. Wind slabs will become more reactive on sun exposed slopes as temperatures rise. Even a small wind slab may wake up the deep persistent problem.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Wind slab avalanched have stepped down to the deep persistent slab since the last storm meaning large triggers can influence this basal weakness. The likelihood is slowly increasing for this high consequence avalanche problem.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 3.5

Valid until: Mar 18th, 2023 4:00PM

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