We are experiencing Deep Slab Instability RIGHT NOW!  Avalanche conditions have been at Considerable for some time now and the reason is that we are still suffering from those weak layers of snow that are near ground level.  This video does a good job of pointing out that sometimes stronger thicker slabs trick us and lure us out into dangerous terrain.  As he explains though we have some weak layers at the bottom of the snowpack and there are often trigger points or spots that have thinner slabs on top of them and if disturbed those spots can quickly propagate and cause large and dangerous avalanches.  It takes a long time for this type of snowpack to heal and become stable.  Be sure to keep all of these things in mind when traveling in the backcountry!