A significant warmup and an already unreliable snowpack provide the ingredients for an avalanche cycle. Without a significant re-freeze Friday night, the danger will rise quickly, especially on solar aspects.
Through these fluctuating conditions, we will list the highest expected rating of the day.
50-90 cm of settled snow overlies weak facets above the Feb 3 interface, which is a crust in most areas. Many natural, human, and explosive-triggered avalanches have occurred on this layer in the past week, and the likelihood of avalanches will increase with high freezing levels and sun.
The sun's effect and overall higher freezing levels will be more pronounced on Friday, and the likelihood of these avalanches will increase as the day goes on, especially on solar aspects.
Some recent avalanches have stepped down to the weak facet and depth hoar layers near the base of the snowpack resulting in large avalanches. This seems to be most common in thin, steep, rocky terrain in the alpine, and will likely increase in frequency.
The avalanche cycle continued this afternoon with ski hill's reporting numerous avalanches up to size 3. An avalanche was reported to have run over Man Yoga (mixed climb), likely size 2 on the Stanley Headwall with additional natural activity in that area. The avalanches reported have been solar triggered.
If the lack of a refreeze materializes, we will see continued activity tomorrow.
The photos below are from yesterday afternoon's avalanche cycle.
Moist snow formed today up to 2500m on all aspects and as high as 2900m on solar aspects. If the inversion materializes we may not have crusts from treeline up to the alpine, but they will be present BTL. Only the highest north aspects will have dry snow. 50-90 cm of settled snow overlies weaker facets above the Feb 3 crust interface, up to at least 2500 m. The base of the snowpack consists of weak facets. Deeper snowpack areas (west of the divide) are more settled and stronger.
Friday night: Valley bottom freezing levels except for an above-freezing layer from 2300m to the alpine (aka no freeze!).
Saturday: 3000m+ freezing levels (high +8C at treeline), with light winds and sunny skies. Valley bottoms are forecast to hit +13C.
Sunday: Much the same, maybe warmer. +15C valley bottom and 3200m freezing levels.
For more details on the weather, click here.
