Avalanche Forecast

Issued: Nov 30th, 2024 2:15PM

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

Avalanche Canada Dvonk, Avalanche Canada

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A slight bump in the danger rating due to the increase in wind and the amount of snow available for transport.

Wind, Wind, Wind! The wind has shown up and is leaving its mark. Windward aspects are becoming scoured and lee features loaded. Caution when entering loaded aspects. Investigate for the presence of windslabs and their reactivity.

Summary

Confidence

Moderate

Avalanche Summary

During a field day to the Hero's drainage significant sluffing was observed off all steep cliffy terrain, On the drive along the Spray, there was evidence of a small Loose dry cycle that appeared to be about 12-24 hours old on steep alpine East faces,

Snowpack Summary

Saturdays field teams traveled through the Hero drainage and towards the purple bowl. On the traverse into the bowl we came across firm slabs that were directly under steeper cliff features. These were more likely spindrift slabs and they did not crack or fail like a windslab would. However the winds were howling and fresh windslabs are likely forming on lee and cross loaded features in Alpine and Treeline elevations. Below this the snowpack in this area was weak, unconsolidated and very thin.

Weather Summary

Saturday: The winds really picked up and are reaching further down into the terrain. Moderate to strong transport was observed off all ridge crests and cliff faces were constantly shedding snow. Temperatures reached -1 at the road elevation (1800m)

Sunday: Clouds with sunny periods, No precip expected. Winds will keep blowing from the West @ 25 km/h. Freezing levels are slowing rising to 1500-1700m over the next couple days.

3 observations from today:

  1. Moderate snow transport from Strong to Extreme West winds in the alpine.

  2. Driving back to Canmore, most trees along the road and hill sides are bare of snow now (evidence of winds in the valley).

  3. Spray lakes ice has thawed out by almost a km since Thursday. (warming temps) & white caps were visible on the open water (Wind).

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.
  • If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.

Problems

Wind Slabs

An icon showing Wind Slabs

Saturday saw a significant increase in winds that were reaching down in tho the valleys. Suspect fresh wind slabs are growing in lee features in the alpine and exposed treeline.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

This slab is sitting on the October crust which has facets above it and provides a good sliding surface. It is more reactive on N and E aspects.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Valid until: Dec 1st, 2024 3:00PM

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