Avalanche Forecast
South Columbia
Another day of sunshine and warm temperatures should keep surface instabilities active. Concern for persistent slab problems is still on the rise.
Check out the Forecasters' Blog for more: http://www.avalanche.ca/blogs/2018-03-09-first-big-warm-up
Avalanche Problem 1: Wind Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Travel and Terrain Advice
- Use ridges or ribs to avoid pockets of wind loaded snow.
- Watch for wind loaded pockets near ridge crests and roll-overs.
Avalanche Problem 2: Loose Wet
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
The chance of loose wet avalanches will once again increase over the day as warm temperatures and strong sunshine break down the cohesion of surface snow. Steep solar slopes are the most concerning.
Travel and Terrain Advice
- Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.
Avalanche Problem 3: Persistent Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Rising temperatures and strong sunshine are increasing concern for weak layers buried deep in the snowpack. In addition to human triggering in thin spots, solar warming and cornice releases are possible natural triggers for persistent slabs.
Travel and Terrain Advice
- Choose regroup spots away from avalanche paths.
- Pay attention to overhead hazards like cornices which could trigger persistent slabs.
- Avoid steep convexities or areas with a thin or variable snowpack.
Avalanche Summary
Reports from Friday included numerous storm slabs and wind slabs ranging from size 1.5 to 2.5. These were triggered naturally as well as with ski cutting and all aspects and elevations were represented. Many recent loose snow avalanches were also observed in the region and in adjacent regions.
On Thursday a snowcat triggered a size 2 persistent slab that failed on the mid-January weak layer when its blade undercut a slope harbouring buried surface hoar.
A handful of very large slab avalanches were reported earlier last week: cornice fall triggered a size 2.5 slab on a north-west aspect at 2700 m and sun triggered a size 2.5 persistent slab on a south aspect at 2200 m. A chunk of falling glacial ice triggered a size 3.5 slab on a north-west aspect.
Avalanche activity is expected to increase as we move into a period of intense sun and prolonged warming. Predictable loose wet avalanches from steep, sunny terrain should be easy to manage. The trickier problem will emerge as warmth penetrates into the snowpack to tickle deeper persistent weak layers. The next few days will be a time to avoid exposure to large sun-exposed features and keep well away from corniced slopes.
Snowpack Summary
Around 20-30 cm of new snow has formed new storm slabs which overlie sun crusts on solar aspects. This latest snow sits on well-settled storm snow from regular snowfalls over the past couple of weeks. Several other sun crust layers may be found within this storm snow on solar aspects.
A couple of layers buried in mid-late February (down around 70-120 cm) are variably reactive, but both have the potential to create surprisingly large avalanches if triggered. Initially, these interfaces were most reactive on solar aspects, where they present as buried sun crusts. However, persistent slabs have been triggered on shady aspects too, where surface hoar and/or facets exist.
Deeper persistent weak layers from January and December are generally considered dormant, but could wake up with forecast warming, a surface avalanche stepping down, cornice fall, or a human trigger in a shallow or variable-depth snowpack area. These layers consist of sun crust, surface hoar and/or facets. Facets linger at the base of the snowpack.
Weather Forecast
Sunday: Sunny. Light south winds. Freezing level to 1900 metres with alpine high temperatures of -1 to 0.
Monday: Sunny. Light south winds. Freezing level to 2200 metres with alpine high temperatures of +1 to +2.
Tuesday: Sunny. Light to moderate southwest winds. Freezing level to 2700 metres with alpine high temperatures of +5.
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.
Wind slabs formed on all aspects during the recent storm and they may remain reactive on Sunday. Extra caution is needed on solar aspects where sunshine could act as a natural trigger and buried sun crust as a sliding layer.