Avalanche Forecast
South Columbia
Steady is the trend. Cold temperatures mean that persistent slab problems will be slow to heal. Stay watchful for signs of wind effect and slab formation at lower elevations.
Avalanche Problem 1: Persistent Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Travel and Terrain Advice
- Surface hoar distribution is highly variable. Avoid generalizing your observations.
- Buried surface hoar is more likely to be preserved in sheltered openings at and below tree line.
- Watch for signs of slab formation, such as wind effect, whumphing, or shooting cracks.
Avalanche Problem 2: Wind Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Shifting winds have been redistributing storm snow into wind slabs on a variety of aspects. Exercise extra caution at lower elevations where winds may have formed a slab over a touchy surface hoar layer.
Travel and Terrain Advice
- Be aware of variable wind loading patterns.
- Use ridges or ribs to avoid pockets of wind loaded snow.
Avalanche Summary
Reports from Monday include observations of a recent Size 2 persistent slab release on a north aspect at 1800 metres, just northeast of Nakusp. Sunday's reports included observations of several older Size 1-1.5 natural wind slab releases, mainly on south aspects in the alpine. One report showed a skier-triggered Size 1 persistent slab releasing from a north aspect at 2200 metres. Reports from previous days include several more observations of wind slab releases from Size 1-2. Recent observations of persistent slab releases have been more limited, with similar size ranges but generally lower elevation ranges and more focused to north aspects.
Persistent slab avalanche danger remains an ongoing concern in areas where last week's storm snow consolidates into a slab above the December 15 interface. In areas where new snow has not yet consolidated into a slab, expect continued potential for triggering loose dry avalanches in steep terrain.
Snowpack Summary
Last week's storm brought 50-80 cm of new snow to the region. Predominantly north winds have since redistributed this storm snow into wind slabs on a range of aspects at higher elevations while cold temperatures have inhibited slab formation elsewhere. Cold has also worked to decrease cohesion and reactivity in older wind slabs.
The storm snow lies over a variety of old surfaces, including large surface hoar (weak, feather-like crystals), crusts formed by sun or wind, and sugary facets. The bond at this old snow interface is of critical importance in areas where the overlying snow has consolidated into a slab. The most concerning areas are those that saw pronounced surface hoar development before the storm, such as sheltered areas at and below treeline. Recent snowpack tests show wide ranging reactivity at this interface but suggest that it may be most reactive on northerly aspects.
A crust formed by rain in late November is another major feature in the snowpack, found approximately 90-120cm deep at tree line elevations. Recent evidence from adjacent regions suggests it may be reactive in steep, variably loaded terrain features in the alpine.
Weather Forecast
Wednesday: Mainly cloudy with isolated flurries and a 1-3 cm of new snow. Light southwest winds. Alpine high temperatures of -15.
Thursday: Cloudy with flurries bringing 4-8 cm of new snow, increasing overnight. Light west winds. Alpine high temperatures of -10.
Friday: Cloudy with flurries bringing 5-10 cm of new snow, increasing overnight. Light east winds. Alpine high temperatures of -12
Avalanche Forecasts in your Inbox
Avalanche Canada has switched to an RSS feed for its daily forecasts. This is a much more flexible method that allows automatic delivery to your email inbox, or to an RSS reader of your choice.
What are RSS feeds?
RSS (Really Simple Syndication) is a popular standardized file format allowing up-to-date delivery of web-based content. RSS feeds enable you to receive content updates from websites, delivered to your email through an RSS aggregator (such as blogtrottr.com) or viewed through applications called RSS readers (such as feedly.com).
Set up an RSS feed for your email:
Select a RSS aggregator
- South Columbia URL:
http://www.avalanche.ca/api/forecasts/south-columbia.rss - Copy the url and paste it into the appropriate field of your RSS aggregator.
- Fill in your email address.
- Voila! Watch the Avalanche Canada forecast roll into your inbox.
Forecast Disclaimer
Avalanche Canada's Public Avalanche Bulletin, and other information and services provided by Avalanche Canada, are intended for personal and recreational purposes only.
**THIS INFORMATION IS PROVIDED "AS IS" AND IN NO EVENT SHALL THE PROVIDERS BE LIABLE FOR ANY DAMAGES, INCLUDING, WITHOUT LIMITATION, DAMAGES RESULTING FROM DISCOMFORT, INJURY, OR DEATH, CLAIMS BY THIRD PARTIES OR FOR OTHER SIMILAR COSTS, OR ANY SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, ARISING OUT OF THE USE OF THE INFORMATION.**
The user acknowledges that it is impossible to accurately predict natural events such as avalanches in every instance, and uses the data in this bulletin with this always foremost in mind. The accuracy or reliability of the data is not guaranteed or warranted in any way and the Providers disclaim liability of any kind whatsoever, including, without limitation, liability for quality, performance, merchantability and fitness for a particular purpose arising out of the use, or inability to use the data.
A weak layer of surface hoar buried 50-80 cm deep has potential to produce large avalanches where the overlying snow has settled into a cohesive slab. The greatest caution is needed around steeper, sheltered slopes at treeline and below.