Sensitivity of weak layers may increase as temperatures approach zero degrees. Watch for signs that warming is affecting the snowpack (snowballing, trees dripping, moist surface snow etc.)
Weather Forecast
The warm dry air aloft that has been flooding in from the West producing Chinook conditions will persist through Monday. On Tuesday an "atmospheric river" hitting the coast will make it's way inland. Predictions of how far inland this will push vary, but expect to see increased cloudiness, ongoing warm temps and some precipitation in our area.
Snowpack Summary
Soft snow exists in sheltered areas, but has been stripped off or blown into Wind Slabs by strong SW winds in all open areas. Facetted layers in the mid and lower snowpack remain a concern, particularly in shallow snowpack areas where facetting is more pronounced and triggering is more likely.
Avalanche Summary
Small natural Wind Slab avalanches have been observed recently. A Large (Size 3) Deep Persistent slab avalanche was observed in Alpine terrain last Friday, at 2250m on a North aspect. Triggered by a small Wind Slab hitting a shallow spot, this propagated across the slope into the adjacent deeper snowpack and was up to 2m thick in places.
Confidence
Freezing levels are uncertain
Problems
Deep Persistent Slabs
Deep Persistent Slab avalanches are the release of a thick cohesive layer of hard snow (a slab), when the bond breaks between the slab and an underlying persistent weak layer deep in the snowpack. The most common persistent weak layers involved in deep, persistent slabs are depth hoar or facets surrounding a deeply buried crust. Deep Persistent Slabs are typically hard to trigger, are very destructive and dangerous due to the large mass of snow involved, and can persist for months once developed. They are often triggered from areas where the snow is shallow and weak, and are particularly difficult to forecast for and manage.
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.