Avalanche Forecast
South Rockies
Wind slabs, cornices and deeply buried weak layers are making for tricky conditions. The best approach is to choose conservative terrain, minimize your exposure to overhead hazards and avoid wind-loaded or cross-loaded slopes.
Avalanche Problem 1: Wind Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Travel and Terrain Advice
- Watch for whumpfing, hollow sounds, shooting cracks or recent avalanches.
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Use extra caution as you transition into wind affected terrain.
Avalanche Problem 2: Deep Persistent Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Several deeply buried weak layers have the potential to produce large avalanches reaching run out zones. Cornices have been a recent trigger for very large avalanches. Avoid shallow rocky snowpack areas where human triggering may also be possible.
Travel and Terrain Advice
- Be aware of the potential for large, deep avalanches.
- Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.
- Avoid steep convexities or areas with a thin or variable snowpack.
Avalanche Problem 3: Cornices
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Cornices have triggered very large avalanches recently. Be especially wary of long runout distances in avalanche paths, and the possibility of mature timber being taken out by a surprisingly large avalanche.
Travel and Terrain Advice
- Give cornices a wide berth when traveling on or below ridges.
- Avoid steep slopes below cornices.
Avalanche Summary
On Tuesday we received reports of size 3 avalanches that were likely triggered by cornice fall over the weekend and ran full path to valley bottom. See here for the MIN report.
A widespread natural avalanche cycle occurred Thursday afternoon and overnight into Friday. Several storm slabs and deep persistent slabs to size 4 were reported when visibility improved on Friday. See this MIN post for more information.
These avalanches are failing on weak layers deep in the snowpack and running to valley bottoms. See this video for more details.
Snowpack Summary
About 10-15 cm on new snow and strong to extreme winds have resulted in extensive scouring on windward slopes (generally north and west facing slopes) and the creation of wind slabs on down wind (lee) features higher up, on a wide range of aspects.
The lower snowpack in this region is weak, with two main concerns: A widespread weak layer from mid-December composed of facets, crusts, and surface hoar is 100-150 cm deep. Second, a rain crust with sugary facets buried in late-November is near the bottom of the snowpack. Although the snowpack structure is variable across the region, these persistent weak layers are generally widespread.
The take home message is that weak layers are still active and deserve a lot of respect. The solution is to stick to conservative terrain while avoiding all overhead hazard.
Weather Forecast
TONIGHT: Cloudy, flurries. Accumulation trace. Ridge wind light to moderate northeast. Temperature -20. Freezing level valley bottom.
THURSDAY: Mix of sun and cloud. Ridge wind strong west. Temperature -15. Freezing level valley bottom.
FRIDAY: Mix of sun and cloud, light flurries. Accumulation trace. Ridge wind moderate, northwest. Temperature -12. Freezing level valley bottom.
SATURDAY: Snow. Accumulation 10-15 cm. Ridge wind moderate to strong, northeast. Temperature -20. Freezing level valley bottom.
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 Rockies URL:
http://www.avalanche.ca/api/forecasts/south-rockies.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.
Strong to extreme winds have formed touchy slabs, especially at higher elevations and in wind-exposed terrain. Wind slabs may step down and trigger deep persistent weak layers, resulting in large destructive avalanches.