Avalanche Forecast

Issued: Feb 24th, 2019 3:50PM

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

Sheltered terrain offers the best riding, but be cautious on steep unsupported features where triggering slab avalanches remains a concern.

Summary

Confidence

Moderate -

Weather Forecast

SUNDAY NIGHT: Clear with a few clouds, moderate northeast wind, alpine temperatures drop to -18 C.MONDAY: Mix of sun and cloud with some isolated flurries possible later in the day, possible accumulations of 5 cm, moderate northeast wind, alpine high temperatures around -15 C.TUESDAY: Mix of sun and cloud, moderate northeast wind, alpine high temperatures around -18 C.WEDNESDAY: Cloudy with scattered flurries and localized accumulations of 5 cm, moderate southeast wind, alpine high temperatures around -12 C.

Avalanche Summary

On Saturday, a few small (size 1-1.5) human triggered slab and loose dry avalanches were reported. One large (size 2.5) naturally triggered persistent slab avalanche was observed on a south aspect near Paulson Summit.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 had impressive propagation on buried weak layers (see some examples here and here). Last 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 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. 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 around treeline elevations.
Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Use caution on open slopes and convex rolls Caution around sheltered open areas at treeline and below including cutblocks, gulleys, and glades.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 2.5

Wind Slabs

An icon showing Wind Slabs
Northeast winds have formed fresh slabs in exposed terrain. 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 - 1.5

Valid until: Feb 25th, 2019 2:00PM

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