Regions
Banff Yoho Kootenay.
If the weather forecast is accurate, we should be entering a period of good ski and avalanche conditions. Watch out for windslabs and large freshly formed cornices as we have responded to two very close calls with cornices in the last week!
Weather Forecast
We are returning back to seasonal temperatures for the foreseeable future with good overnight lows and mild daytime highs. Winds should die down by midday Wednesday as we come under the influence of a ridge of high pressure. Skis should be mostly clear with some lingering clouds for the forecast period.
Snowpack Summary
Below 2000 m the snow pack is rain saturated. In the alpine there is 15-20 cm of recent storm snowforming wind slabs on east through north aspects. The midpack above treeline is well settled and overlies a weak facetted base. These basal facets have not been reactive recently, but should still be considered when making terrain choices.
Avalanche Summary
No new avalanches observed or reported today, however Lake Louise and Sunshine reported significant cornice growth and several wind slabs up to size 1.5 being easily triggered on solar aspects yesterday. Wind slabs were far more stubborn to trigger on north aspects due warm temps and rapid settlement.
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.