Vancouver Island Avalanche Bulletin

Vancouver Island Avalanche Bulletin

Date Issued: Tuesday 24 November, 2009

Valid Until: Thursday 26 November, 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:

Fair - Field information remains limited.

Primary concerns:

• Rain which will soak the snow pack and may cause natural and human triggered avalanches.

Weather:

40 to 75cm of snow has fallen over the island mountains since the start of precipitation on Friday. This was accompanied by winds strong at times. The outlook is for rain starting later Tuesday and continuing through Wednesday. Expect 50 to 120mm of water with the higher amounts being on the west coast and north island. Freezing levels will rise over the tops of the island mountains. Thursday will see an easing in precipitaions and freezing levels dropping back down to 1000m and lower by later in the day.

Travel advisory:

Hazard remains in the alpine and at tree line Tuesday thanks to all that new snow and wind which has left wind slab at these elevations. On Wednesday it seems unlikely that anyone will want to travel in the mountains with torrential rains forecast but we’ll advise against it anyway! The effect of rain on this snow pack is somewhat difficult to predict but natural and human triggered avalanches are likely. Also expect mass melting and water discharge at lower elevations well in excess of what is possible with rain only. Rain in these amounts soaking snow could make creek crossings and exposure to drainages in general quite dangerous. With freezing levels dropping on Thursday things will start to ‘lock up” making travel much safer. Keep an eye on temperatures and freezing levels especially later in the storm. If they start to drop before the precipitation has ended it will fall as snow in the higher elevations creating new wind slab and a higher hazard for Thursday. The rate at which temperatures drop is also relevant in terms of the cooling and “locking up” of the snow pack. If warm temperatures linger consider the hazard as moderate. If things cool more quickly it will be low (excepting if rain turns to snow in significant amounts as mentioned above).

Snowpack:

Information about the snow pack is limited.

Avalanche Activity:

No new avalanche activity has been observed however the amount of terrain that has been observed is very limited.

Outlook:

Rain starting later Tuesday and continuing through Wednesday will deliver 50 to 120mm of water with the higher amounts being on the west coast and north island. Freezing levels will rise over the tops of the island mountains. Thursday will see an easing in precipitation and freezing levels dropping back down to 1000m and lower by later in the day.

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.