Avalanche Forecast

Issued: Feb 5th, 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.

Avalanche Canada matt, Avalanche Canada

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It seems we suddenly have a heavy snow year on our hands! While we wait for our windslab problem to sort itself out, stick to sheltered areas with minimal overhead exposure.

Summary

Confidence

Moderate -

Weather Forecast

We are on deck for another snow storm on the Spray. The models show about 10cm by tomorrow evening. But as I look out the livingroom/office window in Canmore, it appears the storm has already started as of 2pm. There seems to be an upslope (easterly flow) component as well. Tomorrow's temperatures will be steady at -12. Winds will shift from a westerly flow to an easterly flow around noon and be light. Snow and wind was just starting to come down on the Spray valley today around 3pm.

Avalanche Summary

An avalanche control run on EEOR had us a bit surprised today. None of the shots produced large slab avalanches, but they did entrain a lot of loose snow. The largest slab triggered was only a 1.5. 

This contradicts what is happening on the Spray. Don't use these results as an indicator on what's happening on the Spray.

Snowpack Summary

Read this line twice:

The snow just keeps coming!

We rarely get to say that! 

With all of this recent snow we are seeing multiple layers of windslabs form. So far this slab complex is bonding OK within itself, but steep, unsupported slopes could have failures within the multiple slabs. The Jan 29th/fresh windslab interface is still concerning. That January layer was exposed for a long time, which typically means it will be slow to bond. That layer could be down as much as a meter in places. Now being a Rockies forecaster, its quite hard to forget the deeper layers. It seems to be cooperating so far and it isn't a huge red flag at the moment, but its still in the back of our minds.

Terrain and Travel

  • Be careful with wind slabs, especially in steep, unsupported and/or convex terrain features.
  • Be careful as you transition into wind affected terrain.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Shooting cracks, whumphs and recent avalanches are strong indicators of an unstable snowpack.

Problems

Wind Slabs

An icon showing Wind Slabs

Our windslab concern involves several slabs that have been built with each passing storm. By tomorrow we'll have had 3 storms that have each made a fresh layer of slabs. Natural activity tells us they are slow to bond within themselves, but also to the Jan 29th layer. We may experience some reverse loading as the winds shift tomorrow.

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Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 3

Valid until: Feb 6th, 2021 3:00PM

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