Our snowpack is currently undergoing a big change from a winter snowpack to a spring one.  During this change stress is applied to the surface as well as deeper layers in the snowpack during the heat of the day.  During this transition human triggered and natural avalanches become increasingly likely during specific times of the day.  

The most likely avalanche problem to be encountered today will be wet loose avalanches.  These will be likely on east and west aspects up to 4000′ and on south aspects at all elevations.  Northerly aspects are unlikely to have wet loose activity, although sensitivity of wind/persistent slabs will increase during the heat of the day (see problem 2+3).

Avoiding traveling on or being exposed to steep solar aspects should be a major consideration today.  Natural wet loose activity has the potential to step down to deeper layers producing destructive slab avalanches.  Timing is key with avoidance of this problem.  Strong melt/freeze crusts will be in place today on solar aspects, as these break down and become moist-wet the hazard will increase.  The first aspect to heat up will be East, followed by South and then finally West and Northwest.  

Incremental snowfall that we have received over the last 10 days rests on a variety of snow surfaces that will affect the likelihood of human triggered avalanches that may occur 1-2 feet in depth.  Bed surfaces range from hard wind board, melt freeze crusts and near surface facets.  The later interface is currently a layer of concern.  New snow depths since the 10th vary significantly across our forecast zone with some areas only having a few inches and others having as much as 2 feet.  In areas with deeper storm totals that overlie near surface facets, human triggered avalanches are possible.  The sensitivity of these slabs will increase during the heat of the day.

Deeper in the snowpack faceted snow exists in most location at and below the 3/17 interface.  A very large natural avalanche occurred on Meteorite on 4/15 that likely was initiated at this interface and then stepped down to the ground (see problem 4).  This is a clear sign that the changing of seasons to warmer temps has the potential to affect deeper layers in our snowpack.

Wind slabs up to one foot in depth exist in specific locations.  Changing wind directions over the last few days has left wind slabs on a variety of aspects on the lee of high elevation ridge lines, cross loaded terrain and catchment features of steep terrain.  Human triggered wind slab avalanches are possible up to one foot in depth in steep terrain.  

The depth, distribution and sensitivity of this avalanche problem is expected to increase over the next 24 hours as north winds are expected to become moderate to strong overnight on the 16th.

Weak snow exists at the base of our snowpack.  On 4/15 our area saw the first deep slab activity occur since late February.  This occurred on Meteorite (see avalanche activity section) and was a persistent slab that stepped down to the ground.  This is a clear indication that depth hoar could produce more activity later in the season while our snowpack is undergoing a transition from a winter snowpack to a spring one.  

This problem is very difficult to assess due its depth and the fact that signs of instability will likely not be present.  You can stack the odds in your favor by avoiding steep terrain that is undergoing rapid changes such as rapid warming and avoiding exposure to large triggers such as cornices.