Human triggered avalanches are likely 1-2+ feet in depth. Our area has received slow incremental snowfall since 4/9, delivering a wide range of new snowfall amounts to our forecast area.  Expect to find  1-2+ feet of new snow since the 9th that recently turned upside down due to an increase in temperature and continued snowfall on 4/14. This set up on its own would be enough to elevate the avalanche hazard, however there are other factors that will add to the hazard today.  North winds are forecasted to increase today up to 25 mph.  This may not sound like a lot, but will be sufficient to redistribute the new snow into areas of wind slab (see problem 2).  In addition, the intensity of the April sun will be promoting wet loose activity on solar aspects and stiffening storm slabs which will increase the sensitivity of new snow in all areas but high elevation north aspects (see problem 3).

The storm snow avalanche problem can be assessed by paying attention to new snow amounts, checking the sensitivity with the new/old interface and taking into account what affects the wind and sun has had on the surface in the area where you choose to travel.  Pay attention to red flags such as shooting cracks, collapsing and natural avalanche activity.  All of these suggest unstable snow that is capable of producing human triggered avalanches.  Cautious route finding and careful snowpack analysis will be very important for safe travel in avalanche terrain today.

This avalanche problem will be less of an issue in areas that have received lower snowfall amounts.

Northeast winds are forecasted to increase today with gusts to 25 mph expected in wind channeled terrain and along high elevation ridge lines.  There is a lot of new snow available for transport.  Winds in the mid 20 range may not sound like a lot, but is definitely sufficient to redistribute new snow into stiffer slabs that will be more sensitive to human triggers.  The moderate winds that we are expecting can make identifying wind slabs more difficult.  Pay attention to wind redistribution in the area you choose to travel and expect to find increased sensitivity in the surface snow on the lee side of high elevation ridge lines, cross loaded terrain and on the lee side of micro terrain.  Wind slabs may have a pillowed look and will be stiffer at the surface than the underlying snow.

Wet loose natural avalanche activity is likely today.  The amount of activity we receive today will depend on the amount of cloud cover that remains throughout the day.  If the sun comes out wet loose activity will be likely on east and west aspects at low elevation, and south at all elevations up to 6000′.  Steep rocky terrain will be the first areas to be affected.  So far this season wet loose activity has been below average.  Generally by this time of year steep solar aspects are beginning to lose mass by way of natural wet loose avalanche activity.  Many of these areas have recently gained mass, creating the potential for more substantial activity once temperatures rise to seasonal norms and wet loose/ wet slab activity begins in earnest.  Temperatures look to slowly stair step up this week but a drastic change is not yet in the forecast.

Timing is key in avoidance of this avalanche problem.  Pay attention to the amount of warmth that is being transferred into the snow surface (Is it becoming moist-wet?).  Avoid traveling on, or being exposed to, steep solar aspects as snow surfaces are becoming moist-wet.  

Weak snow exists at the base of our snowpack.  This weak snow is currently unlikely to be affected due to the strength of old wind affected snow at the 3/17 new/old interface.  Depth hoar may become a concern later in the season if our area returns to a period of major snowfall and the very strong wind damaged layer at the new/old interface starts to break down and lose strength within the snowpack.  As very hard wind slabs break down within the snowpack, a person or machines weight will have a more direct affect on weak layers at the bottom of the snowpack.  In addition,  the increasing intensity of the sun will be putting pressure on deep layers during the heat of the day.

This problem is difficult to assess.  if we do see deep slab avalanches begin to occur in our forecast zone, they will likely first show up on south aspects.  This has not occurred yet, but would be a clear indicator of an increasing potential to see this avalanche problem on other aspects.