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 - Due to the number of field observations
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
Over the last few days reported avalanche activity was limited to cornice falls from ridge crests in high elevation terrain.
Snowpack Summary
Generally light amounts of new snow cover the previous variable snow surface of crusts, surface hoar, dry facetted snow, or wind affected snow depending on aspect and elevation. Thin new wind slabs are likely in exposed lee terrain, and cornices remain large and weak. The 'Valentine's Day' crust is thick and supportive below 2100 m. The late-Jan crust/surface hoar layer is 1-2 m deep in the west, and can be found within the upper metre of the snowpack further east. It is variably reactive in snowpack tests and still the main concern in many areas. The mid-January surface hoar, deeper again, is also a concern in some areas. Deeper weakness are likely to remain dormant for the time being.
Problems
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.