Avalanche Forecast
South Columbia
Prolonged reactivity of storm slabs has earned them a persistent slab label, but the avoidance strategy hasn't changed. Keep it in mind as you navigate around the more obvious wind effect.
Avalanche Problem 1: Wind Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Travel and Terrain Advice
- If triggered the wind slabs may step down to deeper layers resulting in large avalanches.
- Be especially careful with wind loaded pockets near ridge crests and roll-overs.
Avalanche Problem 2: Persistent Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Our mid-March weak layer of crust and surface hoar has been buried by up to 90 cm of storm snow and has shown prolonged reactivity since the last storm. Manage the uncertainty around triggering this layer by sticking to lower angle, supported slopes.
Travel and Terrain Advice
- Use conservative route selection, choose moderate angled and supported terrain with low consequence.
- Minimize exposure to steep south-facing slopes where recent storm snow overlies a crust.
- Use caution around sheltered steep or convex slopes where buried surface hoar may be preserved.
Avalanche Summary
Reports from Saturday included numerous observations of storm slabs releasing naturally as well as with skier traffic and explosives control. Sizes ranged from 2-3, with crown fracture depths varying from 30-100 cm. This activity occurred on all aspects but was focused at alpine elevations and this problem is now being identified as a 'persistent slab'. Wind slab releases made up a large number of observations, noted predominantly on southeast aspects.
Widespread avalanche activity occurred in the top 30 cm of new snow on Friday. Numerous natural and skier triggered size 1 avalanches were reported, with the most reactive conditions on wind-affected slopes at treeline on north and east aspects.
On Thursday, several size 1 skier triggered storm slab avalanches were reported. They were 30-50 cm thick and occurred on north and east aspects above treeline. One of the slabs subsequently triggered a larger size 2 avalanches that ran on the late-March crust. Some natural size 2-3 storm slabs avalanches were also reported in alpine terrain and a cornice fall on a north aspect in the Selkirks triggered a size 2.5 avalanche on an unidentified 2 m deep weak layer.
Snowpack Summary
A variable 5-20 cm of new snow over Sunday night has brought storm snow totals from the past week to a wide-ranging 50-90 cm. with amounts that taper with elevation. The snowfall was initially accompanied by strong west wind and formed reactive slabs at higher elevations. More recent north winds reached extreme, so a mix of stubborn old and newer, more reactive wind slabs can now likely be found on a range of aspects.
Below the wind effect at the surface, a break between storm pulses allowed for the formation of yet another layer of sun crust (south aspects) and surface hoar (shaded aspects) that is now buried by 20-30 cm of new snow. The full depth of recent storm snow sits on a persistent weak layer buried in late-March that consist of crusts below 1900 m and on south aspects, and surface hoar on shaded aspects at higher elevations.
Pockets of surface hoar (buried mid-March) have been reported on shaded aspects at higher elevations and may be found approximately 70-100 cm below the surface.
Deeper persistent weak layers from January and December are still being reported by professional observers, but are generally considered dormant.
Weather Forecast
Tuesday: Mainly cloudy with isolated flurries and a trace of new snow. Light southwest winds. Freezing level to 1300 metres with alpine high temperatures around -8.
Wednesday: Mainly cloudy. Light southwest winds. Freezing level to 1100 metres with alpine high temperatures around -9.
Thursday: Cloudy with flurries bringing 6-10 cm of new snow, continuing overnight. Light southeast winds. Freezing level to 1300 metres with alpine high temperatures around -8.
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.
Strong and shifting winds have been blowing loose snow into wind slabs on a wide range of aspects in wind-affected areas. North winds were the most recent, so be especially cautious around freshly loaded south aspects.