Avalanche Forecast South Columbia

Tuesday 5th February 2019

Avalanche Danger Ratings Tue 5th Feb 4:14PM Danger Ratings Alpine: Moderate Danger Ratings Treeline: Considerable Danger Ratings Below Treeline: Considerable Persistent Slabs Persistent Slabs Wind Slabs Wind Slabs

Avalanche Canada Forecaster: kdevine

Date Issued:

Valid Until:

The unusual danger rating is due to a buried weak layer that exists mainly at treeline and below. It is easily triggered by humans and there is the potential for large avalanches at lower elevations. Choose low angled terrain, especially in the trees

Confidence

High -

Weather Forecast

TUESDAY NIGHT - Clear periods / north winds 10-15 km/h / alpine low temperature near -19WEDNESDAY - Mainly sunny / northwest winds 10-15 km/h / alpine high temperature near -16THURSDAY - Mainly cloudy with light flurries, 3-5 cm / southwest winds 10-20 km/h / alpine high temperature near -12FRIDAY - A mix of sun and cloud with scattered flurries / northeast winds, 10-15 km/h / alpine high temperature near -15

Avalanche Summary

Natural avalanche activity began to slow down on Sunday, but a persistent weak layer that was buried in mid January continues to be reactive to human triggers. This layer is sensitive enough for humans to trigger avalanches remotely (from a distance). Human triggered avalanches up to size 2.5 were reported on both Sunday and Monday. This MIN report of an avalanche in the Slocan area on Sunday illustrates the continued reactivity of the mid January layer.Widespread avalanche activity was reported on Friday and Saturday. Numerous natural and explosives triggered avalanches to size 3, and human triggered avalanches to size 2 were reported. Many of these avalanches were triggered remotely (from a distance) and failed on the mid January layer.

Snowpack Summary

20-70 cm of recent new snow sits on wind slab, surface hoar (feathery crystals), facets (sugary snow) and a crust on sun-exposed slopes. In many areas, recent winds have formed wind slabs on all aspects due to shifting wind directions. The most notable feature in the snowpack at this time is a persistent weak layer that was buried in mid January, which is now buried 40-90cm. This layer consists primarily of surface hoar, however there is also a crust associated with it on sun-exposed slopes. This layer is the most prominent at treeline and below, and continues to produce avalanches.

Persistent Slabs Persistent Slabs

Likelihood

Likely - Possible

Expected Size

1.5 - 3

40-90 cm of snow sits above a weak layer of surface hoar (feathery crystals) and crust. This layer continues to be reactive to human triggers.

Any steep opening in the trees should be treated as suspect right now.Choose low angled terrain.

Aspects: All aspects.

Elevations: Treeline, Below Treeline.

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Wind Slabs Wind Slabs

Likelihood

Possible

Expected Size

1 - 2

20-70 cm of recent snow has been redistributed by recent winds in many areas, forming wind slabs on all aspects due to a shift in wind direction.

Be careful with wind loaded pockets, especially near ridge crests and roll-overs.If triggered, wind slabs may step down to deeper layers and result in even larger avalanches.

Aspects: All aspects.

Elevations: Alpine.

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