Avalanche Forecast

Issued: Feb 16th, 2021 4:00PM

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

Timothy Johnson,

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The Tonquin Area is officially open for winter travel. Use caution as this is typically more shallow and therefore a weaker snowpack.

Summary

Weather Forecast

Wednesday: A mix of sun and cloud. Alpine temperature: High -13 C. Ridge wind NW: 10 km/h.

Thursday: A mix of sun and cloud. Alpine temperature: Low -16 C, High -12 C. Ridge wind southwest: 10 km/h.

Friday: A mix of sun and cloud with isolated flurries. Precipitation: Trace. Alpine temperature: Low -16 C, High -10 C. Ridge wind SW: 15-35 km/h.

Snowpack Summary

Moderate to strong SW winds and higher humidity are likely creating wind slabs in the alpine on lee features. The upper snowpack has facetted from the recent cold temperatures and overlies a supportive mid-pack, except in shallow areas where the entire snowpack is weak and facetted.

Avalanche Summary

On Sunday one sz 3 avalanche (wind slab) observed from extreme, alpine, north aspect terrain. No other avalanches observed.

Confidence

Due to the number and quality of field observations

Problems

Wind Slabs

An icon showing Wind Slabs

Moderate to strong SW winds in the alpine and higher RH values are likely creating wind slabs.

  • Travel on ridgetops to avoid wind slabs on slopes below.
  • If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Loose Dry

An icon showing Loose Dry

The likelihood of triggering increases with warming temperatures and solar input. Isolated, sheltered features that have not been impacted by winds are susceptible to sluffing and loose dry avalanches. Ice climbers be aware of these features.

  • Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 1.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

  Caution in thin snowpack areas where triggering is more likely. This is a low probability but high consequence problem.

  • Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

1.5 - 3

Valid until: Feb 17th, 2021 4:00PM