Avalanche Forecast

Issued: Feb 23rd, 2019 3:18PM

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

Avalanche Canada shorton, Avalanche Canada

Use extra caution on slopes getting hit by the sun, slabs avalanches are possible to trigger at all elevations.

Summary

Confidence

High -

Weather Forecast

SATURDAY NIGHT: Cloudy with isolated flurries and trace accumulations, light wind, alpine temperatures drop to -15 C.SUNDAY: Sunny with cloudy periods, light northeast wind, alpine high temperatures around -12 C.MONDAY: Mix of sun and cloud, light northeast wind, alpine high temperatures around -14 C.TUESDAY: Cloudy with scattered flurries and localized accumulations of 5 cm, moderate southeast wind, alpine high temperatures around -14 C.

Avalanche Summary

Preliminary reports from Saturday indicate more small (size 1) avalanches were triggered in the latest storm snow. On Friday, numerous small (size 1) storm slab avalanches were triggered by riders in steep terrain.Human triggered avalanches were reported everyday between February 12 and 20. Although most avalanches were small (size 1-1.5), some have shown impressive propagation on buried weak layers (see some examples here and here). On Tuesday, a notable size 3 persistent slab avalanche occurred on an east aspect at 2000 m. This avalanche was triggered by explosives and failed on the persistent weak layer that was buried on February 7th.

Snowpack Summary

The latest storm has brought 15-25 cm of low density snow that now covers variable wind slabs at higher elevations and sun crusts on south-facing slopes. Fresh wind slabs may be forming in exposed terrain.A weak layer of surface hoar (feathery crystals) and a crust that was buried on February 7th is now 30-50 cm deep. This layer has been reactive, and has produced avalanches as large as size 3. Two other surface hoar layers are buried 50 to 80 cm deep the snowpack (referred to as the February 1st and mid-January layers). Although they have not been reactive recently, they are still being monitored by professionals. These layers are most prevalent below treeline on shady aspects. The lower snowpack is considered generally strong.

Problems

Persistent Slabs

An icon showing Persistent Slabs
It remains possible to trigger an avalanche on one of the surface hoar or crust layers buried 30 to 80 cm deep. These layers are most prominent at treeline and below.
Caution around sheltered open areas at treeline and below including cutblocks, gulleys, and glades.Use caution on open slopes and convex rolls Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Wind Slabs

An icon showing Wind Slabs
Fresh wind slabs are possible to trigger at higher elevations. Old wind slabs also linger on a variety of aspects.
Use caution in freshly wind-loaded features, especially near ridge crests and in steep terrain.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Feb 24th, 2019 2:00PM

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