Avalanche Forecast South Columbia

Monday 4th February 2019

Avalanche Danger Ratings Mon 4th Feb 4:45PM Danger Ratings Alpine: Considerable 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:

Natural avalanche activity has slowed down, but human triggered avalanches remain likely, especially in wind loaded areas and at lower elevations where a buried surface hoar layer has produced avalanches recently.

Confidence

Moderate -

Weather Forecast

MONDAY NIGHT - Clear periods / northeast winds 10-15 km/h / alpine low temperature near -14TUESDAY - A mix of sun and cloud / northeast winds 10-15 km/h / alpine high temperature near -13WEDNESDAY - Mainly sunny / northwest winds 15-25 km/h / alpine high temperature near -15THURSDAY - Cloudy with flurries, 5 cm / southwest winds, 15-35 km/h / alpine high temperature near -12

Avalanche Summary

Natural avalanche activity slowed down to some degree on Sunday. Several natural avalanches to size 2, explosives triggered avalanches to size 2.5 and human triggered avalanches to size 2 were reported. Several of these were triggered remotely (from a distance) and failed on a persistent weak layer that was buried in mid January.This MIN report of an avalanche in the Slocan area 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. A persistent weak layer that was buried in mid January 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 has been most reactive at treeline and below.

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.

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.

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.

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