Strong winds on 3/3 and today (3/12) have built windslabs on lee aspects up to 1 foot in depth, deeper in spots that received the strongest winds. The addition of snow from the 3/9-3/11 cycle may contribute to the load. These wind slabs have been deposited on a snowpack with poor structure created by the February drought/cold. Near surface facets have been observed underneath new windslabs, this may keep wind slabs reactive longer than what is typical. This setup is less prominent as you move towards the coast.

As you move farther from the coast the chances increase for shallower wind slabs to step down to deeper persistent layers.

Februarys’ cold and dry weather caused faceting to occur in our snowpack. There is a lot of variability in our forecast area, but generally as you move north, poorer structure exists. 1-2 mm near surface facets exist underneath the 2/1 windboard. This layer of windboard varies in depth, thickness and hardness through the range, but in many areas is 2 feet down, up to a foot thick and pencil hard. Faceted snow beneath this wind affected snow is very difficult to affect due to its thickness and density, but could be triggered from thin areas of the slab, with large loads or changing weather. At this point triggering an avalanche at this layer is unlikely, but may reactivate as the season moves on and the windboard breaks down allowing a persons weight to penetrate the layer or as heat pushes deeper into the snowpack.

It will be important to keep an eye on these layers once precipitation returns to our area. The most likely areas to affect deeper persistent slab avalanches will be in the Continental zone, in rocky terrain where a thinner/more faceted snowpack exists. Careful snowpack assessment is necessary while traveling in the Continental zone.