Weather Forecast
A strong ridge of high pressure will persist through the forecast period bringing dry conditions, sunny skies, and warmer temperatures. On Friday/Saturday freezing levels may rise to 1600m in the afternoon, then drop to valley bottom at night. Ridgetop winds should generally be light from the South. Maximum alpine temperatures near -1. Sunday brings alpine sun, valley cloud, and possibly temperature inversions.
Avalanche Summary
No new natural avalanche activity has been reported. On Tuesday two size 2 slab avalanches were reported in the Dogtooth range on Repeater Ridge. These occurred on a East aspect @2400m. On Monday explosive avalanche control done in the Dogtooth Range produced 2 avalanches up to size 2, running full depth to ground basal facets. These were on NW-N aspects, @ 2300m.
Snowpack Summary
Wind slabs are likely to be found on exposed areas at treeline, and above into the alpine. Storm slabs can be found at all elevations. They seem to be settling out quick, but still show sensitivity to rider triggers; especially on stepper slopes and convex rolls. Below this sits a pretty, well settled mid-pack. Yet, there are a few exceptions. The Jan. 13th SH/FC combo has been reactive in ski hill testing. Remember this is somewhat of a modified snowpack when compared to a true backcountry uncontrolled snowpack. Regardless, I feel like we can't take our eyes off this layer just yet, remember, it's only a couple weeks old.The mid December facet layer is buried approx. 80 cm on the east side and 200+ cm on the west side. This layer seems to have more energy in the Purcells than any other region in the province and was reactive on Jan. 28th, when a skier remotely triggered a size 3 avalanche. At this point we're looking at a low probability high consequence situation.There are basal facets at the ground which remain a concern, especially on Northerly aspects at high elevations. During the earlier part of the week a couple of slab avalanches have occurred, running down to these basal weaknesses. Snowpack depths at 2000m sit near 2m deep.
Problems
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.