Avalanche Forecast

Issued: Mar 17th, 2020 4:00PM

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

Avalanche Canada shorton, Avalanche Canada

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Little change is expected due to a stable weather pattern. Be extra cautious as slopes warm up throughout the day.

Summary

Confidence

Moderate - Uncertainty is due to the limited number of field observations.

Weather Forecast

A high pressure system brings clear dry conditions for the week.

TUESDAY NIGHT: Clear skies, light northeast wind, freezing level drops to valley bottom, alpine temperatures drop to -10 C.

WEDNESDAY: Clear skies, light north wind, freezing level climbing to 1500 m, alpine high temperatures around -3 C.

THURSDAY: Sunny with a few clouds, light south wind, freezing level climbing to 1700 m, alpine high temperatures around -2 C.

FRIDAY: Sunny, light southwest wind, freezing level climbing to 1900 m, alpine high temperatures around -1 C.

Avalanche Summary

On Monday warm sunny weather resulted in several wet loose avalanches on south-facing slopes in steep rocky terrain around Duffey Lakes. One natural size 2 slab was observed on a northeast alpine feature in the northern part of the region. Some large glide slab releases were reported around the Coquihalla.

Over the weekend a few small (size 1) wind slab avalanches were triggered by riders in northern parts of the region.

Looking forward, daily warming will likely cause more wet loose avalanches and potentially weaken cornices and lingering wind slabs. In northern parts of the region, the warming trend has potential for the deep persistent slab problem to reawaken.

Snowpack Summary

Surface conditions are highly variable with a mix of crusts, moist snow, and hard wind slabs. The surface will become moist on sun-exposed slopes and at lower elevations throughout the day.

In the northern part of the region (i.e. Duffey/Hurley/Gold Bridge), a deep instability may linger at the base of the snowpack. It has not produced an avalanche since Feb 17. If one were to trigger the layer, it would likely be in a thin, shallow, rocky spot. A cornice fall could also trigger it.

Terrain and Travel

  • Carefully evaluate steep lines for wind slabs.
  • Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
  • Back off slopes as the surface becomes moist or wet with rising temperatures.

Problems

Wind Slabs

An icon showing Wind Slabs

Triggering wind slab avalanches remains possible after strong northeast wind formed slabs in atypical terrain features last week.

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

In the north of the region (e.g. Duffey, Hurley, Gold Bridge), a deep persistent weak layer of faceted grains near the ground presents a lingering concern on steep, shallow slopes in the alpine.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3.5

Valid until: Mar 18th, 2020 4:00PM