Pay attention to conditions that change with exposure to wind, and maintain margins around wind-drifted features. Continue to monitor for the presence of weak snow near a crust.
Strong southwest winds and recent snow have formed wind slabs in lee terrain features at upper elevations that may remain possible to trigger. With winds shifting to the southeast, there is potential for fresh reactive slabs to build in a cross-loaded pattern on Monday.
In the north of the region, a layer of weak facets (sugary snow) can be found down 50-70 cm near a crust that formed in early December. In the neighboring Sea to Sky region, this layer has demonstrated recent instability, and it may be possible to trigger.
A short burst of southeast wind on Monday
Sunday night: Mainly cloudy, up to 5 cm of snow, winds shifting to southeast and increasing to moderate, treeline temperatures near -9 C, freezing level near valley bottom.
Monday: Mainly cloudy, up to 5 cm of snow, moderate southeast easing to light, treeline temperatures near -8 C, freezing level around 500 m.
Tuesday: Mix of sun and cloud, light variable winds, treeline temperatures near -10 C, freezing level at valley bottom.
Wednesday: Cloudy, isolated flurries with trace accumulations, light southeast winds, treeline temperatures near -7 C.
Early Saturday morning, operators in the north of the region reported a natural avalanche cycle releasing several large (up to size 2.5) and one very large (size 3-3.5) avalanches breaking within the storm snow.
In the neighboring Sea to Sky region, we received reports of four large (size 2-2.5) explosive-triggered persistent slab avalanches failing on the early December crust/facet layer. These occurred on northwest and northeast aspects around 2000 m.
An impressive storm over the weekend brought 35-45 cm of new snow to northern parts of the region and 60-90 cm to areas in the south. Strong southwest winds had an ample supply of snow to drift into wind slabs at upper elevations. It remains possible to trigger these wind slabs in lee terrain features, such as down-wind of ridges and roll-overs. A shift in wind direction from southwest to southeast on Monday may form fresh reactive wind slabs in a tricky cross-loading pattern. Monitor for changing conditions as you move into wind-exposed terrain and pay attention to cracking or hollow sounds.
In the north of the region, weak faceted snow can be found 50-70 cm deep on a crust that formed in early December. This layer has shown reactivity in the neighboring Sea to Sky region. This persistent slab problem warrants careful evaluation and conservative route-finding as the recent snow consolidates into a more cohesive slab over the weak layer.
The south of the region has seen substantially higher snow totals over the past week, with areas near the Coquilhalla seeing over a meter of accumulation since Monday. Expect to find deeper snow accumulations above the December crust and anticipate larger slab avalanches. Having endured warmer temperatures and more rainfall, the southern part of the region is just reaching the threshold for avalanches at most elevations.
