Avalanche Forecast

Issued: Mar 13th, 2023 4:00PM

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

Avalanche Canada jsmith, Avalanche Canada

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15-25 cm new snow and moderate south wind have formed fresh storm slabs that will likely be most reactive in wind affected terrain.

Use small low consequence slopes to test the bond of the new snow.

Summary

Confidence

Moderate

Avalanche Summary

A rider triggered size 1 wind slab on a north aspect in the alpine was reported on Sunday.

Snowpack Summary

15-25 cm new snow and moderate south wind have formed fresh storm slabs that will likely be most reactive in wind affected terrain.

Below the new snow are a variety of surfaces. These include surface hoar (3-10 mm) on shady slopes at all elevations, wind affected surfaces at treeline and above, and sun crust on sunny aspects.

The mid-snowpack is generally strong but the lower snowpack is a different story.

The November facets are still prominent at the base of the snowpack. They are showing signs of improving but this layer remains a significant concern in rocky, shallow, or thin to thick snowpack areas at treeline and above.

Weather Summary

Monday Night

Partly cloudy with isolated flurries; 3-10 cm / 20 km/h southwest ridgetop wind / Low temperature at treeline around -13 C / Freezing level valley bottom

Tuesday

Mix of sun and cloud with isolated flurries; 0-3 cm / 30 km/h southwest ridgetop wind / High temperature at treeline around -10 C / Freezing level 1000 m

Wednesday

Mix of sun and cloud / 30 km/h west ridgetop wind / High temperature at treeline around -9 C / Freezing level 1100 m

Thursday

Sunny / 10 km/h southwest ridgetop wind / High temperature at treeline around -7 C / Freezing level 1400 m

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Make conservative terrain choices and avoid overhead hazard.
  • Use small low consequence slopes to test the bond of the new snow.
  • Avoid exposure to slopes that have cornices overhead.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Storm slabs in motion may step down to deeper layers resulting in large avalanches.

Problems

Storm Slabs

An icon showing Storm Slabs

15-25 cm new snow and moderate south wind have formed fresh storm slabs that will likely be most reactive in wind affected terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

A weak layer of facets exists near the base of the snowpack. The likelihood of human triggering is low given the layer's depth, but large triggers such as cornice failures or smaller avalanches in motion have the potential to produce very large avalanches with surprisingly wide propagation. Suspect terrain for human triggering includes steep, shallow, and rocky terrain where the snowpack transitions from thin to thick.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2.5 - 4

Loose Wet

An icon showing Loose Wet

Expect natural wet loose avalanches on steep sunny aspects when the sun comes out.

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 1.5

Valid until: Mar 14th, 2023 4:00PM