Selkirk Mountains

Warming temperatures will drive avalanche conditions today. As the day progresses wet loose avalanches becoming a growing threat as the surface snow warms and loses cohesion. Recent snow and rain have added weight to the weak snow grains around the December 7 crust, and today’s meltwater could further lubricate them. A loose wet avalanche could trigger a larger, more dangerous slab avalanche. The travel advice is simple - steer clear of steeper slopes to avoid both wet snow problems and triggering a larger, more dangerous avalanche.

Today we are still making sense of the active weather that hit our region earlier this week and culminated with snow, rain, more snow, then strong winds on Wednesday. Rain and heavy wet snow deposited a crust/slab on top of soft dry snow from earlier in the week. Differences in amounts of rain/snow fall and temperature varied across the area based on location and elevation; with more northerly and higher elevations receiving more snow and less rain, while southern and lower elevations received more rain. This has created a complex patchwork of crusts and wind drifts.

Yesterday and today’s mild weather should go a long way towards stabilizing the upper snowpack, but the persistent problem around the December 7th Rain Crust remains, and warm temps today mean loose wet are a problem around the compass rose and at all elevations. Thin supportable snow surfaces at upper elevations are likely to deteriorate more quickly than thick lower elevation ones.

The persistent slab problem is always a tricky one as the problem layer is now buried close to two feet deep and its easy to ignore, especially with all the recent happenings in the upper snowpack. But the problem continues to linger and as it gets buried deeper triggering an avalanche on it becomes an increasingly unlikely but high consequence possibility. Recent snow and rain have added weight, while rain and melt water may perculate deep into the snowpack to lubricate weak layers. As supportable surface conditions soften with today’s warm-up the likelihood of punching through and initiating an avalanche from shallowly buried trigger points, such as near cliffs, rock outcroppings, trees and stumps, increases.

Look for rapidly changing conditions as temperatures rise today. Crusts that are supportable in the AM may not be by early afternoon. Pinwheels, snow bombs falling out of trees and snow glomming onto skis and skins are all classic signs that the surface snow is wet and has lost cohesion. Softening snow may increase depth below surface to impact weaker snow layers. A loose wet avalanche has the potential to step down, causing a larger avalanche on the persistent weak layer. If you start to notice these its time to head back to the rig.

The avalanche problems may be a little complex today, but the travel advice isn’t: avoid steeper slopes to avoid wet problems and you'll avoid the bigger persistent slab problem too.

FIRST AVALANCHE FATALITY 2024-25:

We are saddened to report that the first avalanche fatality of 2024-25 occurred in the mountains northwest of Cascade, ID near Lookout Peak. A group of two snow bikers triggered an avalanche, and one was caught and fully buried. The slide was reported to be relatively small, but the rider was carried into a terrain trap and buried deeply. He was found with an avalanche beacon and extricated, but did not survive. The accident occurred just south of the Payette Avalanche Center forecast area. Our sincere condolences go out to those impacted by this incident.