Regions
Northwest Inland.
Fat wind-loaded slopes below ridge crests and convoluted rocky areas with a shallow snowpack are the two types of places where a little extra caution is a good idea.
Confidence
Low - Due to the number of field observations
Weather Forecast
Over the next few days the storm track will be aligned with the Canada USA border. The Northwest will generally be dry, clear, and with below freezing temperatures.Tuesday: Mostly sunny, no precipitation, light to moderate northeast wind, and treeline temperatures around -10 CWednesday: Mostly sunny, no precipitation, moderate northwest wind, and treeline temperatures a few degrees below freezing.Thursday: Mostly sunny, no precipitation, moderate north wind, and treeline temperatures around -5 to -10 C.
Avalanche Summary
We have limited field observations to draw from so the lack of reported avalanche activity reflects both and absence of activity and survey effort.If you're out in the mountains and see recent avalanches please snap a photo and submit your information to the Mountain Information Network
Snowpack Summary
The inland region picked up 5 to 15cm of new snow over the weekend accompanied by wind that was largely out of the west, but there were periods of southeast wind recorded too. This new snow rests on a wide variety of old surfaces including small facets, crusts on solar aspects and stubborn old wind slabs near ridge crest. In protected areas below 1500m the new snow may be sitting on previously formed feathery surface hoar.Two crusts formed near the end of November are found approximately 30 to 50cm below the surface. These crusts are widespread and extend into the alpine. Previous snowpack tests produced hard results on these crusts, but we have not seen any recent information about their sensitivity to triggering. Below these crusts, a well settled mid-pack overlies the late October crust which is down near the ground. The October crust is widespread and has not been reactive to human triggering since the end of November. Average snowpack depths in the region are between 80 and 140cm at treeline, with up to 160cm in the alpine.
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.
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.