Watch for fresh slab formation this weekend, especially in wind exposed terrain. If there's more than 30 cm of new snow in your location the danger may well be high. Central & northern areas have weak layers 40 to 70 cm below the surface which remain a concern for triggering.
Persistent problems are more common in thinner, colder snowpack areas of the region (for example Pine Pass, Tumbler Ridge, Kakwa) than in warmer and deeper areas (like Renshaw or Torpy).
Strong northwest and southwest wind combined with new storm snow is expected to build wind fueled storm slabs in open terrain behind ridges. It's possible that slabs will form further dowslope away from ridge crests and in open areas near treeline.
Saturday looks to be a storm day and then the weather is a bit quieter Sunday & Monday. The latest model runs are showing a pretty juicy storm system for the region Monday night into Tuesday, stay tuned for more details.
FRIDAY NIGHT: Freezing level at valley bottom, strong west/northwest wind switching to strong southwest by dawn, trace of snow possible.
SATURDAY: Overcast, freezing level between 500 and 900 m, strong southwest wind, 1 to 10 cm of snow expected.
SUNDAY: A few clouds, freezing level at valley bottom, light southwest wind, no significant precipitation expected.
MONDAY: A few clouds at dawn building to overcast by sundown, freezing level at valley bottom, strong southwest wind, no significant precipitation expected during the day, potential for 5 to 20 cm Monday night.
Last week's storm resulted in a natural avalanche cycle in Pine Pass and northern areas that released either at the bottom of the storm snow or in a deeper weak layer. In the south and west areas there were fewer reports of avalanches and they were small.
Looking forward, the weather forecast suggests strong wind events with some new snow; even without additional snow there's enough on the ground available for transport so I expect natural wind slab activity on lee slopes with it primed for human triggering.
On Friday 15 to 30 cm of new snow fell across the region, this snow likely comes to rest on surface hoar in many locations.
Over the last week, northern and western areas of the region received 30 to 50 cm of new snow, eastern and southern regions received much less with anywhere from a trace to around 25 cm. That means deeper snowpack areas have around 250 cm on the ground near treeline, thinner areas have around 100 cm.
Layers of concern vary through the region too. Areas around Pine Pass and Tumbler have, within the top 40 to 80 cm, surface hoar and facet/crust layers formed in late November that are reactive in snowpack tests. We think they exist around treeline elevations throughout the region, and can likely be found in alpine terrain as well.
The lower snowpack contains several crust layers, which could be a concern in shallow areas along the eastern slopes of the region. Having said that, we have little to no information from places like Kakwa.
In the west (e.g. Torpy) and south (McBride) where the snowpack is deep it is also stronger and missing some of the weak layers.
Throughout the region a new layer of surface hoar is being buried -- here's a pic from our NoRo field team.
