Don't let the amazing riding lure you out into the biggest terrain features just yet, we've got active persistent slab problems in play that may remain sensitive to human triggering.
Aging wind slabs at upper elevations may remain sensitive to human triggering, especially in step terrain near ridge crest. Wind slab avalanches in motion could step down to buried weak layers and release very large persistent or deep persistent slab avalanches.
30 to 60 cm of settled snow rests above a widespread layer of surface hoar that produced numerous avalanches last week. These slabs have been most sensitive to triggering at treeline.
Recent loading from new snow and wind has aggravated our region's deep persistent slab problem. Some very large and destructive avalanches have been sporadically failing on deeply buried weak layers, predominantly on north through east aspects in the alpine. Cornice falls are a likely trigger for these slabs.
The storms just keep coming.
SUNDAY NIGHT: Freezing level at valley bottom, moderate southwest wind, trace of snow possible.
MONDAY: Overcast, freezing level near valley bottom, moderate southwest wind, 4 to 8 cm of new snow during the day, 5 to 10 cm Monday Night.
TUESDAY: Overcast, freezing level rising to about 1000 m, strong southwest wind, 5 to 10 cm of snow during the day, 1 to 5 cm Tuesday Night.
WEDNESDAY: Broken cloud cover, freezing level at valley bottom, moderate west/northwest wind, trace of snow possible.
Avalanche activity slowed down Saturday, aside from the observation of some older wind slabs in steep terrain very little avalanche activity was observed.
Last week there were reports of wind slab, persistent slab (failing on the February 19 surface hoar layer), and deep persistent slab (failing on basal facets) avalanches. This pattern highlights loading and surface avalanches from recent stormy weather straining multiple weak layers in the snowpack.
Reports from Thursday showed several more wind and storm slab avalanches from size 1-2 (small to large) releasing naturally as well as with skier and snow machine traffic in the Kispiox area. North through east aspects again proved most reactive.
On Wednesday a cornice failure in the same area initiated a size 3 wind slab avalanche on a northeast facing feature at 1600 m that cleared out large timber in the valley. The recent storm snow was sensitive to human triggering, even in low angle terrain, running on the March 1st surface hoar. A few shallow natural wind slabs were also observed in steep terrain.
Cornice falls have been a common trigger for slabs on the slopes below them. On February 28th a cornice fall triggered a size 3.5 deep persistent slab on a northeast facing slope at 1800 m.
The Wednesday into Thursday night storm produced 5 to 25 cm of new snow with the deepest accumulations found in the south and accompanied by strong east/southeast wind. The snowpack is now quite variable as evidenced in this MIN report from Saturday.
Loading from new snow and wind has made several persistent weak layers problematic over the past week. A combination of surface hoar and sun crust layers were buried on February 19 and currently sit 30-60 cm below the surface that seem to be most sensitive to human triggering at treeline elevations.
A couple of weak layers that formed in January are buried in close proximity to one another 80-140 cm below the surface. Below that, an early season crust/facet layer lurks at the base of the snowpack.
