Avalanche Forecast

Issued: Feb 22nd, 2023 4:00PM

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

Avalanche Canada mconlan, Avalanche Canada

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Touchy wind slabs remain on atypical slopes due to strong northeast wind. Any incident in cold weather may be serious.

Summary

Confidence

Moderate

Avalanche Summary

We received reports of a wind slab avalanche cycle caused by the northeast wind. The avalanches were large (size 2 to 3) and mostly on southeast to southwest slopes.

Looking forward, the cold weather may mean that newly formed wind slabs could remain human-triggerable for the coming days. These slabs are likely on atypical south to west aspects due to the northeast wind.

Snowpack Summary

Northeast wind produced touchy wind slabs in lee terrain features in wind-exposed terrain. Wind slabs are most prevalent on south to west aspects, which is atypical. These slabs may remain reactive for a few more days due to frigid weather limiting bonding.

A small layer of surface hoar crystals may be found below the 50 to 100 cm of storm snow from the past week, particularly in areas sheltered from the wind around treeline.

Large and weak facets that formed in November are found near the base of the snowpack. Although the likelihood of triggering this layer is low at this time, the consequence of doing so would be high. This layer is most likely to be human-triggered in thin, rocky slopes at alpine and upper treeline elevations.

Weather Summary

Wednesday Night

Mostly clear skies with no precipitation, 20 km/h northeast wind, treeline temperature -26 °C.

Thursday

Mostly clear skies with no precipitation, 10 to 20 km/h northeast wind, treeline temperature -25 °C.

Friday

Increasing clouds with no precipitation, 20 to 40 km/h southwest wind, treeline temperature - 20 °C.

Saturday

Cloudy with snowfall, accumulation 5 cm, 20 to 40 km/h south wind, treeline temperature -14 °C.

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.
  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • 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.

Problems

Wind Slabs

An icon showing Wind Slabs

Northeast wind formed touchy wind slabs on atypical south to west aspects. Travel conservatively and assess for slab development prior to committing to high-consequence terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 3

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

A layer of large and weak facets sits near the base of the snowpack. This layer is most prominent in upper treeline and alpine elevations and continues to produce sporadic, destructive avalanches. Human-triggering is most likely on steep, shallow, rocky slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2.5 - 4

Valid until: Feb 23rd, 2023 4:00PM