Avalanche Forecast

Issued: Feb 20th, 2019 4:22PM

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 kdevine, Avalanche Canada

Though avalanche activity has slowed down, it is worth keeping in mind that the potential still exists for humans to trigger persistent slab avalanches. While these avalanches are becoming less likely, the consequences remain high.

Summary

Confidence

High -

Weather Forecast

WEDNESDAY NIGHT - Mainly clear / north winds 10-20 km/h / alpine low temperature near -18THURSDAY - Mainly sunny / southwest winds 10-20 km/h / alpine high temperature near -12FRIDAY - Mainly cloudy with flurries, 5 cm / south wind 15-35 km/h / alpine high temperature near -13SATURDAY - A mix of sun and cloud with isolated flurries / northeast winds, 15-35 km/h / alpine high temperature near -14

Avalanche Summary

No new slab avalanches have been reported since Saturday. Several loose avalanches to size 1 have been reported recently.On Saturday, a persistent slab avalanche was triggered by a skier on a north aspect on a 30 degree slope. Check out the MIN report here. These sorts of avalanches are becoming less frequent, but they are still possible and the consequences are high.There was also evidence of large avalanches (up to size 3) that were triggered by strong wind in the north of the region on Saturday.On Friday, two more small to large (size 1 to 2) persistent slab avalanches were triggered by humans. They were 50 to 70 cm deep and released on the mid-January surface hoar layer described in the Snowpack Summary. They occurred at treeline and alpine elevations on north to northwest aspects.

Snowpack Summary

Depending on location, the snow surface varies from 10-30 cm of low density snow, to hard wind slab with softer wind slabs in the mix as well. Winds have been from a variety of directions, so wind slabs may be found on all aspects, mainly in the alpine and at treeline.A weak layer that was buried in mid January is now buried anywhere from 30-60 cm. This layer consists of surface hoar (feathery crystals) and facets (sugary snow). The layer also likely consists of a crust on south facing slopes.  Avalanche activity on this layer has slowed, but test results still indicate that this layer may still be easy for humans to trigger in certain locations.  It has been most reactive at treeline and below treeline.The lower snowpack is considered generally strong.

Problems

Persistent Slabs

An icon showing Persistent Slabs
Approximately 50 cm of snow sits above a persistent weak layer of surface hoar that was buried in mid-January. The surface hoar may sit on a crust on south aspects.
Avoid steep, open and/or sparsely treed slopes at and below treeline.Use conservative route selection, choose moderate angled terrain with low consequence.Be aware of the potential for wide propagation.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

Likelihood

Possible

Expected Size

1.5 - 2.5

Wind Slabs

An icon showing Wind Slabs
Parts of the region have been hit hard by winds, which formed wind slabs in the lee of terrain features on a variety of aspects. If triggered, there is potential for a wind slab avalanche to step down to a buried persistent weak layer.
If triggered, wind slabs may step down to deeper layers and result in even larger avalanches.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Feb 21st, 2019 2:00PM

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