Current avalanche conditions are complex. Stay very cautious in your approach to the mountains this weekend.
Confidence
Fair - Due to variable snowpack conditions
Weather Forecast
Saturday: Light winds out of northwest. Freezing level at valley bottom. No significant snowfall. 1500m temp: -10Sunday: Light ridgetop winds out of the N increasing to moderate NW after lunch. Freezing level at valley bottom. No significant snowfall. 1500m temp: -10Monday: Strong NW winds at ridgetop. Freezing level at valley bottom. Isolated flurries, no significant accumulation.Tuesday: Freezing level forecast to rise to 2000m
Avalanche Summary
Our field team reported numerous small avalanches on Thursday from the Inverted Peak area. In the nearby Lizard Range avalanches were intentionally triggered by skiers and explosives resulting in avalanche to size 2 on all aspects. I suspect a thorough look around the South Rockies would reveal a similar pattern.
Snowpack Summary
The South Rockies snowpack is fairly complex at the moment. Here's the highlights: Around 50 cm of storm snow fell in favored locations earlier this week. This snow rests on a myriad of old surfaces (January 4th interfaces) that include sun crust on steep south and west facing terrain, surface hoar in sheltered locations at treeline and below and facets everywhere else. We don't have a good handle on exactly where the surface hoar is and is not. As a result, you need to dig frequently to confirm the presence or absence of surface hoar/sun crust/facets on individual slopes if you're thinking about jumping into complex or challenging terrain.The wind during the storm was primarily out of the SW, but the winds have been all over the map since then. As a result I'm suspect of wind slabs on all exposed slopes at and above treeline. The midpack is well settled and strong with one or two (location specific) crusts deep in the snowpack. These crust/facets combos are largely dormant, with the only concern being triggering from a shallow snowpack area or with a heavy trigger.
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.
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.