Selkirk Mountains

Most slopes are generally safe from avalanches. Upper-elevation slopes that face west through north to southeast where older wind-drifted slabs override weaker snow is where you might triggering a small avalanche. You can find these potentially problematic spots below ridgelines and in gullies that look filled-in, rounded, or pillow-shaped.

Today’s a bit of a ground hog day as far as avalanche conditions are concerned offering more of the same - generally safe conditions prevail across our forecast areas. The stable high-pressure ridge providing clear, cold conditions has contributed to formation of Surface Hoar and near-surface faceting in the upper 15 to 30 cm of the snowpack. These cohesionless grains have improved overall surface riding conditions, but sit above a fairly stout crust that formed after rain up to about 7,000 feet on November 22 and 23. Multiple days of steep diurnal temperature swings has promoted faceting both above and below the crust.

The biggest talking point today is that the avalanche hazard and danger rating are likely to change with the incoming precipitation forecast to hit our area Saturday and lasting through the weekend. Expect the avalanche hazard to rise as rain and snow add weight to the upper snowpack and stress buried weak layers.

Over the last week, field observations report various flavors of faceting ranging from large Surface Hoar grains to a pile of near-surface facets on wind-sheltered and shady aspects, and newly formed faceted sun crusts on southerly-facing slopes. Weakening or softening of the upper snowpack has made it more difficult for a rider or machine to trigger an avalanche that breaks in older snow layers. Snowpack tests are requiring harder force to initiate a failure in these collapsible snow layers, and the overlying slab has become soft enough to help limit propagating failures in Extended Column Tests.

Digging deeper, the lower snowpack benefited from mild temperatures and bountiful snowfall during the first couple of storms in November. More or less steady snowfall limited the opportunity for the snow surface to facet and therefore, the bottom of our snowpack currently lacks widespread, discernable weak snow layers for most areas – the caveat are in places where overall snow depths are still less than 3 feet deep.

Multiple rain crusts lurk throughout the snowpack and recent field observations have noted small, faceted grains starting to form around the November 23 crusts – primarily at elevations around 6,000 feet and higher. The fact this upper crust is close to the surface and directly affected by steep temperature gradients, we should anticipate these facets will not get stronger but only further weaken. These lingering persistent grains will likely come back into play once the next stormy period adds more load and stress.

Despite generally stable conditions at present, travel through the mountains with an investigative mindset. You can use small non-consequential test slopes to look for signs of instability before choosing to step into bigger, steeper terrain. Observing how weak the snow surface is on different aspects and elevations now will help you avoid an avalanche encounter once the snow train rolls back into the station.