Avalanche Forecast
Purcells
Variable amounts of new snow throughout the region has been redistributed by recent southwest switching to southeast wind. Additionally when the sun comes out this time of year it usually packs a punch - steep southerly slopes are suspect right now.
Avalanche Problem 1: Wind Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
Travel and Terrain Advice
- Stay off recent wind loaded areas until the slope has had a chance to stabilize.
- Be cautious as you transition into wind affected terrain.
- Use caution on steep open slopes and convex rolls
Avalanche Problem 2: Persistent Slabs
What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?
An interface buried up to 70cm deep has "woken-up". This problem seems most reactive in south-facing terrain where buried crusts exist.
Travel and Terrain Advice
- Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.
- Carefully assess and consider avoiding southerly facing slopes
- Watch convoluted terrain with variable snowpack depth and multiple trigger points.
Avalanche Summary
On Thursday there was report of naturally occurring size 2.5 persistent slab avalanche on northeast facing slope at 2400m. This was from a heavy trigger of glacial ice. Prior to that avalanche activity consisted of mainly wind slabs (skier triggered and skier remote) in the size 1-1.5 range. However, we've also received reports of persistent slab avalanches (to size 3) where recent accumulations have been the highest. These avalanches, were skier-triggered or remotely triggered (from a distance) on Monday and naturally occurring on Tuesday with wind loading on cross-loaded slopes. We suspect the buried sun crust buried mid-February. Deep persistent avalanche activity has become less frequent over the past week.
Snowpack Summary
Up to 50 cm of recent storm snow (in the south and west parts of the region) has been redistributed into wind slabs in wind-exposed terrain by south and southwest flow. Up to 60cm below the surface there's a layer buried mid-February that's a sun crust on solar aspects, and spotty surface hoar on sheltered slopes. This layer looks most concerning on on solar aspects where it's associated with with small facets or surface hoar above.
There are several deeper layers that have shown signs of improving but still remain suspect as low probability - high consequence avalanche problems. We are talking about surface hoar layer buried back in December and January. Near the base of the snowpack is a November crust combined with loose sugary faceted snow. These layers may "wake-up" with strong inputs such as sustained warming, sustained snowfall, large triggers (e.g. cornice fall or smaller avalanches coming down from above); human triggering is also possible in shallow snowpack areas with convoluted terrain.
Weather Forecast
SATURDAY: Flurries, accumulation 5-15cm Friday night into Saturday / Light east wind / Alpine temperature -8
SUNDAY: Cloudy with isolated flurries / Light west wind / Alpine temperature -7
MONDAY: Mix of sun, cloud and isolated flurries / Light to moderate west wind / Alpine temperature -8
NOTE: The convective flurries which are common during this time of year can result in widely varying snowfall amounts throughout a region. These spring squalls routinely drop 20+ cm of snow in one valley while the adjacent drainage remains dry. For this reason, the distribution of avalanche problems associated with new snow, such as wind slabs, can vary greatly within a region.
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
- Purcells URL:
http://www.avalanche.ca/api/forecasts/purcells.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.
New snow and several days of southerly wind means localized slabs on the leeward side of ridges and on cross-loaded slopes and gulleys. Storm slabs may also be found in sheltered areas on steeper slopes and rolls.