Avalanche Forecast

Fair - Freezing levels are uncertain on Thursday

The Kootenay Boundary should see 10cm during the day Monday and another 5 cm Monday night. Tuesday starts out clear & cold accompanied by light northwest winds. The freezing level climbs to 800m Tuesday, falling back to the surface overnight. On Wednesday warm air floods the region, as a result freezing levels climb to 2000m. Winds should be moderate out of the W at treeline Wednesday, Strong out of the NW at ridgetop. Thursday looks to be the warmest day with the freezing level climbing to 2200m in the afternoon.

On Sunday the wind, warmth and new snow came together to produce a natural avalanche cycle which averaged size 2, but did produce one size 3. It sounds like a few avalanches stepped down to the Mid-Feb Surface Hoar. The majority of the action involved more superficial soft slab avalanches with crowns 5 - 10 cm in depth. The Bonningtons harbor a weaker snow structure than most of the region; On Sunday cornice fall triggered a size 3 avalanche in low angle terrain (25 - 30 degrees) This avalanche was on a N-NE facing slope, the crown line is reported to be 80 - 120 cm in depth. Conditions Monday are very similar to Sunday and I expect natural avalanche activity to continue.

Sunday & Monday were warm windy days in the mountains. Stagleap Wx station at 2140m reached -0.9 C Sunday at 11:00. This warmth has changed the character of the supper snowpack, allowing it to settle & gain strength. Ski quality has suffered a bit, but, in the long run this will help to heal our snowpack. In the short term there are two problem layers to watch; A. The Feb. 29 interface which consists of surface hoar on shady aspects and a thin sun crust on south aspects, down around 30cm. B. Surface hoar buried mid-February, which is now down 70-120cm and still giving sudden snowpack test results. 10+ cm is forecasted for Monday afternoon which will hide the cohesive slab beneath.We often think about cold temperatures “locking things up.” Tuesday dawns cold & cloudy, but 10+ cm's from Monday will insulate 100cm of very warm snow that rests on the mid Feb SH. With this structure in place, we need to give the snowpack some extra time to adjust. Continue to stay conservative in your terrain selection Tuesday and be sure to factor the surface hoar problem into your decision making as you travel in the mountains Tuesday. The surface hoar problem is far from over.