A very strong inversion is currently moving into place that is pushing temperatures well above freezing at upper elevations.  Nicks weather station was recording 38° at 4200′ at 5 am.  Unusual weather can produce unusual avalanche patterns.  This will be the first time temperatures have gone above freezing above 4000′ in a long time.  Density changes within the most recent storm or buried surface hoar down 2-3 feet may become reactive today.

Buried surface hoar exists around 2-3 feet deep in the intermountain and continental zones on all aspects above 2500′.  A significant natural avalanche cycle during the 1/23-25 storm (see avalanche activity section) occurred at this interface.  This layer was found to be reactive in stability tests at ~5000′ On Girls glacier as recently as 1/27.  Above freezing temperatures at upper elevations will be adding stress to weak snow increasing the likelihood of human triggered avalanches up to 3 feet in depth.  

Signs of instability may not exist even when dangerous conditions are present.  Digging snowpits is the most effective way to identify where this layer is present and its sensitivity.   Although, this can be a difficult assessment tool due to spatial variability (conditions that vary from place to place) and results that may be confusing or misleading.

Weak snow exists near the base of our snowpack in all three climate zones.  Recent heavy snowfall and rising temperatures has increased the stress upon this weak snow.   The likelihood of deep human triggered avalanches has gone from unlikely to possible.  This layer will be difficult to directly affect by a person or machine but a persistent slab avalanche (see problem 1)  may be able to step down to deep layers in our snowpack.  DOT avalanche mitigation efforts did just this on the buttress to the east of nicks(see avalanche activity section), showing that it is still possible for deep layers to produce avalanches.