Vancouver Island Avalanche Bulletin

Vancouver Island Avalanche Bulletin

Date Issued: Friday, January 30, 2009

Valid Until: Sunday, Feb 1, 2009

Bulletin Area: This bulletin covers the mountainous region of Vancouver Island from the Mt. Cain Ski Area in the North to the Beaufort range to the South including the mountains of Strathcona Provincial Park.

DANGER RATINGS

Confidence:

Good: Light precip is forecasted for the south coast over the next few days with FZL’s dropping.

Primary Concerns:

Isolated wind slabs in the alpine and at Treeline

Deep facet layers still prevalent  where a trigger in the right spot could still initiate large destructive avalanches in alpine terrain

Weather:

A ridge of high pressure will push a major low  to the North coast through Friday.  Low precipitation levels are expected and freezing levels although will rise with the onset of the warm front are forecasted to lower and remain low for this forecast period. Little snow with strong winds on Friday morning diminishing with the passing of the front. The possibility of up to 5cms over the next 3 days.

Snowpack:

Treeline and below our pack consists of a very strong upper and mid pack.  Melt-freeze crusts and strong dense layers in between are producing no shears and non reactive to ski testing.  A layer of weak facets formed from the previous cold snap lurks just below the surface which could pose problems with additional loading on it in the future. On sunny aspects this now has a thin melt-freeze crust on it. Evidence of a major wind event in the alpine was observed on Wednesday with major redistribution of the snow from exposed areas and loading lee features.  Major scouring has occurred on most windward faces. No evidence of natural activity was observed within this redistributed snow and with the warm temps over the last few days it seems to have settled out.

Our main concern is still the deep facet layer near the ground.  This layer is gaining strength at Treeline but still poses a threat in the alpine.  This is the kind of layer that will only be triggered from the right spot such as a thin area or from a large load such as a cornice drop.  If is does go however the potential for a very deep, very hard slab avalanche is great.

Travel advisory:

Take Extra caution in areas lee to the wind.  With the wind event in the last storm there could be wind slabs lurking.  Be wary of thin alpine terrain especially that with smooth ground cover such as glaciers or thin scree slopes.  Steep alpine terrain is still not advised. Deep hard slabs are very hard to predict and evaluate.  These layers are not the kind of layer you can “feel” while skiing and are usually triggered from areas of weakness.

A forecaster did back off on a classic North facing, 35 degree, convex feature with smooth ground cover and the weak facet layer near the base on Thursday.

Remember that in Moderate conditions human triggered avalanches are possible with a need to be increasingly cautious in steep terrain.

Operators across the water in a very similar snow pack to ours are still reporting very low confidence and still making conservative terrain choices in the alpine.

Avalanche Activity:

No new avalanches have been observed.

Outlook:

The potential for some snow on sunday with the next pacific front.

Are you traveling in the island back country?

Send our forecasters your observations. We are particularly interested in hearing if you have observed avalanche activity or If you or a member of your party has been involved in an avalanche. Email your observations to the Island Avalanche Bulletin forecasters at info@islandalpineguides.com

Important Notice: This is a regional forecast and significant variation may exist within the forecast area. The information and danger ratings are intended as a trip planning aid for recreational, backcountry users of avalanche terrain; they are not meant to be used as the sole factor in determining the avalanche danger presented by a specific slope. Always include local weather, snowpack and avalanche observations in your decision to travel in avalanche terrain. Observations and experience may lead to different conclusions from what is reported or recommended. See disclaimer for further details. The technical data used to produce these bulletins is obtained from a variety of sources, including local ski areas and remote weather resources.