Avalanche Forecast
North Columbia
Recent avalanche activity has been extensive. Deep weak layers have reached a tipping point and are producing historic avalanches.
A Special Avalanche Warning is in effect in this region. Copy this address to view details: http://bit.ly/2nSOUyX
Avalanche Problem 1: Storm Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Travel and Terrain Advice
- Avoid exposure to sun-exposed slopes.
- Choose low-angled, sheltered terrain where new snow hasn't been wind-affected.
- If triggered, storm slabs may step down to deeper layers and result in very large avalanches.
Avalanche Problem 2: Persistent Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Several unstable weak layers are lurking deep in our snowpack. These layers have the potential to be triggered both naturally and with skier or rider traffic. When triggered, these layers have been producing very large avalanches that run far.
Travel and Terrain Advice
- Use conservative route selection. Choose low-angle, supported terrain with low consequence.
- Avoid the runout zones of avalanche paths. Very large avalanches have been running full path.
Avalanche Summary
Reports from Thursday included observations of numerous natural storm slab releases, generally from size 1-2.5 but with several outliers reaching size 3.5 to 4.5. These larger examples featured crown fractures up to 500 metres wide with runout distances of up to 3 km. These historic slides destroyed mature timber along their edges as well as on opposing slopes. Several more recent persistent slabs were observed to have run naturally from size 2.5-3.
On Tuesday, numerous storm slabs were triggered naturally, by explosives, and skiers. They were small to large (size 1 to 2), on all aspects, with depths from 20 to 40 cm. Persistent slab avalanches were large (size 2 to 3), explosives-controlled, 100 to 200 cm deep, on all aspects, and generally releasing on the late-November crust.
Looking forward, it will be essential to maintain elevated caution as danger ratings shift into the CONSIDERABLE range. As the likelihood of triggering avalanches diminishes, the consequences and destructive potential of avalanches will remain dangerously high.
Snowpack Summary
Recent accumulations of 25-70 cm have formed reactive new storm slabs on the surface throughout the region. In some areas the new snow has buried a new layer of surface hoar. About 150-250 cm of storm snow from the past two weeks now overlies an unstable snowpack with four other active weak layers.
1) 150 to 250 cm of snow sits on the crust and/or surface hoar layer from mid-January. The crust is widespread, except for possibly high elevation north aspects. The surface hoar was reported up to tree line elevations and possibly higher.
2) The early-January weak layer is 170 to 270 cm below the surface. It is composed of surface hoar on sheltered slopes as well as sun crust on steep solar aspects and is found at all elevation bands.
3) Another weak layer buried mid-December consists of a facet/surface hoar/crust combination, which is buried 200 cm or more below the surface. It is most problematic at and below tree line.
4) A crust/facet layer from late November is yet another failure plane responsible for recent very large avalanches.
The wide distribution and ongoing reactivity of these layers suggests that choosing simple terrain free of overhead hazard is the best avoidance strategy.
Weather Forecast
Saturday: A mix of sun and cloud with thicker valley cloud due to a temperature inversion. Light southwest winds, strong at high elevations. Alpine high temperatures of -12. Cooler at lower elevations.
Sunday: Mainly sunny with increasing cloud over the day. Light north winds. Alpine high temperatures of -10, cooling over the day as the temperature inversion breaks down.
Monday: Mainly sunny with some valley cloud due to another temperature inversion establishing. Light variable winds, increasing overnight. Alpine high temperatures of -10, slightly cooler at lower elevations.
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
- North Columbia URL:
http://www.avalanche.ca/api/forecasts/north-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.
Heavy snowfall and steady winds have formed reactive new storm slabs. Natural avalanches have been numerous and the potential for human triggering is high. Strong solar effect and alpine winds may act as a trigger for natural avalanches on Saturday.