Northwest Mountains

Over the past week, it has slowly become harder for you to trigger an avalanche.  You are more likely to trigger a dangerous avalanche near and above treeline due to variations in slab thickness.  Slopes that are obviously shallow, rocky, or have variable depths due to wind effect should be avoided.  If you are unlucky enough to find a trigger point and release an avalanche on upper elevation leeward terrain it will be large and dangerous.  Low elevation features provide safer terrain options as the snowpack depth is more uniform with fewer trigger points.  

Change is constant within the snowpack, but the speed at which change happens can vary greatly depending on the weather.  During periods of stable weather the change occurs at a slow rate and incrementally improves avalanche conditions.  The last small loading event was on February 16th (this storm favored the Ruby Range with most other areas only receiving a few inches), and the last major loading event was February 13th.  Upper elevations received several bouts of wind-loading over the past two weeks spurring some natural avalanche activity, but sheltered terrain has not received a loading event for two weeks.  This lack of loading below treeline has given weak layers time to adjust to the slabs above and incrementally decrease the chances for you to trigger an avalanche.  Slabs and weak layers can be easily found below treeline, but they have become unreactive to the weight of a person (take a look at this recent observation from Washington Gulch to see an obvious slab/weak layer structure but with stability test that indicates it is unlikely for human triggering).  For these reasons, the danger rating has been dropped to LOW for the Northwest Mountains where the snowpack is deeper and slabs are thicker.  In the Southeast Mountains, the snowpack is generally shallower with thinner slabs which increases the chances for you to initiate failure in the weak layer.  It would be prudent, even below treeline, to continue to read terrain and the snow cover to identify and avoid shallow, rocky, or extreme terrain.  The 'landmines', or trigger points, below treeline have become isolated across the landscape.  Triggering an avalanche below treeline is unlikely, but not impossible in the Northwest Mountains.

Drifted, upper elevation slopes offer a greater degree of uncertainty.  You can be confident that the potential avalanche size is larger as compared to below treeline slopes, but the variation in slab thickness due to rocky terrain and wind effect is greatly increased and these factors create more trigger points or places for you to impact the weak layer.  Upper elevation terrain has received more recent wind-loading, contains more trigger points, and offers a larger potential avalanche size which all equates to an increased risk for you.  Look for and avoid terrain where you find trigger points like cliff bands, rock outcrops, convex rolls, or great variations in snowpack depth.  You can also choose smaller slopes with runouts free from terrain traps to reduce the consequences if you do trigger an avalanche.

Today's spring-like weather will create some minor wet avalanche concerns by the afternoon.  Strong solar radiation due to the higher-in-the-sky March sun and light winds will allow the surface snow on southerly terrain features to warm.  Loose wet avalanches are expected to remain small and isolated across the landscape.  These conditions are most likely to develop on steep rocky terrain features on the south half of the compass.