Tricky conditions in BC interior

The CAC has issued special public avalanche warnings for both of the previous two weekends. We are considering issuing a third warning for the coming weekend and will make the decision later this week. Regardless of whether a special warning is issued, I thought I should give everyone a heads up on conditions.

The snowpack will remain highly unstable in many of BC’s interior mountain ranges this weekend. Areas affected include mountainous backcountry terrain in:

• The North Rocky Mountains north and east of Prince George, including the mountains around:
  • Mackenzie.
  • Pine Pass.
  • Chetwynd.
  • Tumbler Ridge.
  • Kakwa Recreation Area.
  • The Columbia Mountains (Cariboo, Selkirk, Monashee, and Kootenay Ranges) from Prince George south to the US border and:
    • East of Quesnel, Williams Lake, 100 Mile House, Kamloops, and the Okanagan Valley.
    • West of the Kootenay River, Columbia River/Kinbasket Lake, and Fraser River.
    • The South Coast Mountains:
      • North and east of Pemberton.
      • West of Lilloet and Lytton.

The upper 100cm of the snowpack has up to five or six embedded weak layers, all of which are buried and out of sight. Any of these layers alone would present a significant challenge but in combination they have produced an extremely complex avalanche problem. These layers are proving to be exceptionally persistent—they have been very active for over two weeks and show no signs of improvement. In fact, conditions are becoming trickier and more complex every day.

Avalanches are starting naturally with minor changes in weather such as light accumulations of new snow, winds blowing a bit of snow around, warm temperatures, or even just sun shining on a slope when clouds break for a short period. The CAC is receiving daily reports of sledders, skiers, and snowboarders triggering avalanches, often from very low angle terrain (as flat as 15-20 degrees) and sometimes from as far as 50 – 100 metres away.

There is no indication avalanche activity is abating. In recent days, avalanche sizes have been increasing. Slides big enough to demolish a pickup truck  are now occurring regularly. A recent report described avalanches 1000 metres across and running 1000 metres down-slope. These events are not survivable if you are caught in one you trigger yourself, or if one is triggered above you and it runs you down.

Extensive experience and professional level safety procedures and guidance are required to manage the current avalanche risk. Backcountry recreationists are urged to stay away from avalanche terrain until the snowpack becomes more stable. If you go into the mountains, you can reduce the chance of an avalanche accident by:

• Staying within ski area boundaries.
• Cross-country skiing at or near valley bottom.

Unless there’s a significant change in weather, the problem will likely persist into the following week, through next weekend, and perhaps longer. Look for up to date information about avalanche safety, education, and conditions at: www.avalanche.ca.

Please feel free to forward or repost this message freely.

You can send observations, photos, or comments to: forecaster@avalanche.ca, 250-837-2141 ext. 230.

You can contact me directly at: kklassen@avalanche.ca, 250-837-2141 ext. 227.

Karl Klassen

Public Avalanche Bulletins Manager

Canadian Avalanche Centre, Revelstoke