Vancouver Island Avalanche Bulletin

Vancouver Island Avalanche Bulletin

Date Issued: Thursday 11 February, 2010, 22:00hrs.

Valid Until: Sunday 14 February, 2010.

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

Note: If precipitation amounts play out as forecast below the HIGH ratings for the alpine and tree line on Friday and Saturday will likely be CONSIDERABLE for the east and north island and HIGH only for the west coast.

Confidence:

Good.

Main Concerns:

• Storm snow.
• Wind slab.
• Rain triggering slab avalanches and loose snow avalanches below the snow line when snow turns to rain Saturday.

Weather:

Precipitation was generally light over the island mountains until around mid day Wednesday when the current system made land fall and started to deliver some appreciable quantities of rain and snow. By time of writing the lastest readings (21:00PST Thursday) show that the island alps had seen between 15 and more than 50mm of water. The greatest amounts have been on the east coast of the island at 50mm and above in places while the west coast has seen around 40mm. The north island has had about 15mm. Freezing levels have come up to 1400-1500m later today bringing rain below about 1200m and very wet snow at least to tree line. Winds have been gusting strong with the onset of the heavier precipitation.

The outlook is for continued precipitation with 10 to 45mm of water Friday, 30 to 80mm Saturday and easing to showers Sunday. The greatest amounts on Friday and Saturday are forecast for the west coast with about half as much on the east coast and the lowest values forecast for the north island. Freezing levels look to be ranging from 800 to 1300m until they spike later Saturday to 1700 or 1800m. The exception here seems to be parts of the north island (Mount Cain in particular) where models seem to agree that the spike will not hit above about 1300m. Winds will be from the SE through SW with an emphasis on the SW at 40 to 70kph.

Avalanche Activity:

No new avalanches have been observed during the previous forecast period.

Snow Pack:

We expect that with all of this new snow we will be seeing failures in the unsettled new snow, at the new snow/old surface interfaces as well as below at shears which were still evident in the previous storm snow. Also surface hoar has been observed at some locations which may render results.

Travel Advisory:

With so much new snow and strong winds we expect to be seeing a natural avalanche cycle in the alpine and at tree line on Friday and on Saturday. Travel in avalanche terrain is not recomended in those areas at those times. Another cycle will likely take place Saturday when snow turns to rain at around tree line and below on the west and east island (looks less likely on the north island). If the thought of playing in the mountains in the rain is not enough to keep you away perhaps the increased avalanche hazard when this warming takes place will do the job. This will likely last into early Sunday at which point faling freezing levels and slowing precipitation will allow things to calm down a little. Though the natural cycle will ease up Sunday, wind slab will be widespread at tree line and above and will be easily triggered by humans. Exercise extra caution if you decide to go into the alpine on Sunday. Do so only if you have advanced route finding and snow stability evaluation skills. Be aware that you will still be able to trigger avalanches at tree line and below on Sunday. All of this new snow, warm temperatures and strong winds are fine ingredients for big cornice growth. Give these unpredictable beasts a wide berth.

Outlook:

Continued precipitation with 10 to 45mm of water Friday, 30 to 80mm Saturday and easing to showers Sunday. The greatest amounts on Friday and Saturday are forecast for the west coast with about half as much on the east coast and the lowest values forecast for the north island. Freezing levels look to be ranging from 800 to 1300m until they spike later Saturday to 1700 or 1800m. The exception here seems to be parts of the north island (Mount Cain in particular) where models seem to agree that the spike will not hit above about 1300m. Winds will be from the SE through SW with an emphasis on the SW at 40 to 70kph.

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.