Tuesday is forecast to be a cooler day than Monday. If warming persists, there will be a higher likelihood of avalanche activity, especially on steep, sun-exposed slopes.Are you a member of Avalanche Canada? Join today at avalanche.ca/membership
Confidence
Fair - Wind effect is extremely variable
Weather Forecast
The current ridge of high pressure will persist for Tuesday and Wednesday bringing a mix of sun and cloud to the forecast region. By Wednesday evening a pacific frontal system will make its way into the Columbia Mountains, although only overcast skies and trace amounts of snow are expected on Thursday. Ridge top winds are forecast to be strong from the northwest on Tuesday, and then become light on Wednesday and Thursday. Freezing levels should hover around 1500m on Tuesday, and then drop to about 800m on Wednesday and Thursday.
Avalanche Summary
On Sunday a size 2 natural cornice fall was reported from the region. Also, wind slabs to size 1.5 were reported to have been triggered over the last few days on high elevation south-facing terrain. Current wind slabs may remain sensitive to human triggering while forecast strong northwest winds may promote new wind slab activity on south-facing slopes
Snowpack Summary
Up to 10 cm of recent snow covers the previous variable snow surface of surface hoar, crusts, dry facetted snow, or wind affected snow depending on aspect and elevation. The "Valentine's Day" crust is just below the surface and is now strong and thick in most places. New wind slabs may have formed in lee terrain from recent W-NW winds, and cornices remain large and weak. The late-Jan crust/surface hoar layer (up to 100 cm deep) and the mid-January surface hoar (80-120 cm deep) are generally dormant, and chances of triggering these weaknesses have decreased. However, triggering may be possible with a large input such as cornice fall, or an avalanche stepping down, especially on sun drenched slopes.
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.