Avalanche Forecast

Issued: Mar 20th, 2023 4:00PM

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

Avalanche Canada JA, Avalanche Canada

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The region is trending towards spring like conditions. Start early and finish early as solar warming is having the strongest effect typically by mid-afternoon.

Wet loose avalanche activity on solar aspects has been consistently triggering the deep persistent layer at all elevations this week.

Ice climbers should choose objectives with no overhead hazard and minimal sun exposure.

Summary

Confidence

Moderate

Avalanche Summary

Several wet loose avalanches observed on Monday occurring mid to late afternoon on Sunday - all elevations southerly aspects with many stepping down to the basal weakness or triggering persistent and deep persistent slab avalanches. One size 3 deep persistent slab on Sunset peak southwest aspect propagated across half of a large alpine bowl feature. Afternoon loose wet cycle continues in the Coleman area 93N just south of Weeping Wall with avalanches reaching the ditch and some spilling onto the highway.

Don't forget to post avalanche observations to the MIN.

Snowpack Summary

Sun crust on solar aspects at all elevations breaking down by early to mid afternoon. Moderate SW winds after March 13th created pockets of wind slab on lee aspects. Approximately 20-30cm down is a buried sun crust at low elevations on steep southerly slopes and a surface facet layer in sheltered terrain. The mid-pack is 40 to 80cm of supportive facetted snow. Near the ground it is generally weak with large facets and depth hoar.

Weather Summary

A ridge of high pressure will remain the dominant weather feature through late Thursday. Tuesday will be clear skies, light northerly winds with the freezing level rising to 2000m. Descent recovery overnight with a low of -12C. Similar conditions on Wednesday with winds changing to westerly and a freezing level up to 2100m. Late Thursday the ridge will give way to a more active pattern with light precipitation forecast for Friday.

Detailed weather forecasts from Avalanche Canada: https://www.avalanche.ca/weather/forecast

Terrain and Travel Advice

  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
  • Be alert to conditions that change with elevation and sun exposure.

Problems

Loose Wet

An icon showing Loose Wet

Loose wet snow avalanche activity is increasing as afternoons are getting dramatically warm. These types of avalanches can be what initiate larger slag avalanches. Temperatures are ranging from -15 at night to +8 in the afternoon.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs

The 20cm of storm snow from March 13th has been periodically blown around, redistributed, settled, and has combined with the larger snowpack structure for the most part. Their is a cornucopia of interfaces throughout the snowpack depending on aspect, elevation, and local terrain influences. There have been a few avalanches this past week which appeared to have stepped down to multiple layers. Sun will increase potential reactivity.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The bottom of the snow pack is inherently weak with well developed Facets and Depth Hoar. Wind slab avalanches have stepped down to the deep persistent slab since the last storm meaning large triggers can influence this basal weakness.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3.5

Valid until: Mar 21st, 2023 4:00PM

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