Avalanche Forecast
Regions: Lizard-Flathead.
Increasing winds will impact loose snow. Expect to find more reactive deposits around ridge features and steep openings at treeline.
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
Saturday night: Mostly cloudy with isolated flurries, up to 5 cm. Moderate SW wind. Treeline low around -10 °C.
Sunday: A mix of sun and cloud. Moderate to strong W wind. Increasing temperatures with a treeline high around -2 °C, possible inversion.
Monday: Sunny. Moderate SW wind. Treeline high around -4 °C.
Tuesday: Increasing flurries, 5 cm. Strong SW wind gusting to extreme. Treeline high around -4 °C.
Avalanche Summary
On Friday, explosives triggered storm slabs to size 2.5, and skiers triggered avalanches to size 2. A large (size 2) natural cornice failure was reported likely having failed in the overnight storm.
Evidence of a natural storm slab avalanche cycle size 2-2.5 was observed on NE aspects Wednesday and Thursday, likely having run during the storm earlier in the week.Â
On Monday and Tuesday, storm slabs were reactive to explosive up to size 2 and ski cuts produced storm slabs and loose dry avalanches up to size 1. By Wednesday, explosive results were limited to size 1 loose dry.
On Sunday, a size 2.5 persistent slab avalanche was triggered on an E aspect at treeline. This avalanche is detailed in a MIN post and features in our latest blog post, Photos of recent persistent slab avalanches in the southern interior.
Snowpack Summary
Another 5-10 cm arriving Saturday morning brough last weeks storm totals to 40-50 cm. In open terrain and upper elevations, wind developed more reactive deposits around lee and convex features. This recent snow covered a hard, faceted snow surface which formed during cold temperatures and may take a little time to bond. Sun and warm temperatures starting Sunday may turn steep solar aspects moist in the afternoon.Â
The most notable layer of concern in the snowpack is a crust that was formed in early December and is now down 100-250 cm. Activity on this layer has been sporadic, the most recent persistent slab avalanche in the region was on January 2. This layer has created a low likelihood, high consequence scenario which is best managed through conservative terrain choices and disciplined backcountry travel techniques.
Terrain and Travel
- Seek out sheltered terrain where new snow hasn't been wind-affected.
- Be aware of the potential for large avalanches due to the presence of a persistent slab.
- Avoid shallow, rocky areas where the snowpack transitions from thick to thin.
Avalanche Problems
Wind Slabs
Increasing winds will impact loose snow. Expect to find more reactive deposits around ridge features. Be especially mindful around steep and convex openings in the trees. The new and recent snow may overlie a weak interface which could result in deeper and touchier than expected slabs.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Likely
Expected Size: 1 - 2
Persistent Slabs
A persistent slab problem formed by a crust down 100-250 cm has created a low likelihood, high consequence scenario that is difficult to forecast. Avoid likely trigger spots such as steep, rocky slopes with a shallow or thin to thick snowpack.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Unlikely - Possible
Expected Size: 2 - 3.5