North Columbia

Fresh wind slabs are sitting on top of buried wind slabs that are sitting on facets (weak, sugary snow). The fresh wind slabs are touchy and the buried wind slabs may remain reactive to human triggers longer than is typical for this region.

High - The weather pattern is stable

TUESDAY NIGHT: Clear / Light to moderate, northeasterly winds / Alpine low -16.WEDNESDAY: Sunny / Light, northeasterly winds / Alpine high -8.THURSDAY: Mostly sunny / Light, northerly winds / Alpine high -8.FRIDAY: Sunny / Light, northwesterly winds / Alpine high -16.

On Monday, several natural wind slab avalanches up to size 1.5 were reported on a variety of aspects in the alpine. Over the past week there have been numerous reports of persistent slab avalanches, some of which were human triggered. They have been large avalanches (size 2-2.5), occurring on a variety of aspects at treeline and below treeline elevations. They are likely failing on the persistent weak layer of surface hoar and/or crusts that were buried mid January. These layers have created a low likelihood, high consequence scenario that requires discipline and careful terrain selection to manage effectively.

Strong northeasterly ridge-top winds on Monday created fresh wind slabs on lee features at treeline and above. Additionally, there are buried wind slabs on a variety of aspects that are sitting on facets (sugary snow) which may cause them to remain reactive to human triggers longer than what is typical for a wind slab problem in this region.There are two prominent weak layers in the upper snowpack. One was buried at the end of January, and the other was buried mid January. They are approximately 40 and 75 cm below the surface. Both layers consist of a mixture of surface hoar (weak, feathery crystals) and facets (sugary snow), which likely also sit on a sun crust on steep, south facing slopes. These weak layers are most prominent at treeline and below treeline elevations.Very sporadically, failures have occurred near the base of the snowpack in this region, or in neighboring regions. These avalanches have primarily been in steep, rocky, high alpine areas with a shallow snowpack.