Avalanche Forecast

Issued: Mar 29th, 2023 4:00PM

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

Avalanche Canada jleblanc, Avalanche Canada

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Be aware of loose avalanches stepping down into persistent weak layers and creating large releases. Approach shallow rocky areas with caution.

Summary

Confidence

Moderate

Avalanche Summary

Wet loose avalanches occurred Tuesday and Wednesday on south aspects throughout the region, as conditions were clear and sunny.

Several dry loose avalanches (size 1) were naturally triggered within the recent snow on steep northerly alpine features near St.Mary's over the weekend.

While activity may have started to taper off on the deeper layers, some locations in the region (especially thin, rocky areas in the alpine) are still of concern.

Snowpack Summary

At upper elevations, up to 15 cm of recent snow was received since Saturday, hich has settled quickly into moist snow at most elevations. This overlies a crust on solar aspects, faceted snow and surface hoar up in shaded and wind-sheltered areas. Wind-affected surfaces are found in exposed areas. At lower elevations, a crust exists on or near the surface.

In the middle of the snowpack, there are at least a couple of lingering persistent weak layers, including surface hoar in wind-sheltered terrain and a sun crust on south aspects. These layers appear to have generally gone dormant, but could still be reactive in isolated areas and should be on your radar in the Purcells part of the region.

The lower snowpack is made up of a widespread layer of large, weak basal facets and depth hoar in some areas, which produced some large avalanches in the Elk Valley and the neighbouring region of Purcells last week. Professionals are still concerned about it waking up.

Weather Summary

The region will be under a building ridge of high pressure, with calm and dry conditions until Friday, when a southwesterly flow will return.

Wednesday night

Clear with cloudy periods. Low alpine temperatures of -10 °C. Light easterly ridge wind. Freezing level at valley bottom.

Thursday

A mix of sun and clouds. High alpine temperatures of -1 °C. Light westerly ridge wind gusting 30 km/h. Freezing level rises to 2000 metres.

Friday

Cloudy with sunny periods. Isolated flurries. High alpine temperatures of -3 °C. Light southerly ridge wind gusting 40 km/h. Freezing level rises to 1800 metres.

Saturday

Cloudy. Isolated flurries. Local amounts up to 5 cm. High alpine temperatures of -5 °C. Moderate westerly ridge wind gusting 40 km/h. Freezing level rises to 1500 metres.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Conditions may have improved, but be mindful that deep instabilities are still present.
  • If triggered loose wet avalanches may step down to deeper layers resulting in larger avalanches.
  • Avoid rock outcroppings, convexities, and anywhere the snowpack is thin and/or variable.

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

The base of the snowpack remains very weak and avalanches are unpredictable. Very large human-triggered avalanches are possible at treeline and above. Avoid thin, rocky start zones and shallow areas with variable snowpack depths where you are most likely to trigger this layer.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Mar 30th, 2023 4:00PM

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