A warm, moist storm systems arrived overnight forming fresh Storm Slabs at all elevations. With a mix-bag of old, snow surfaces below the new snow, dense slabs will be reactive to the weight of a rider. Sensitivity may be a bit touchier on northerly-facing slopes where the old snow surface faceted and weakened during the recent warm, dry spell. In addition, firm melt-freeze crust on slopes facing east through south to west may act as a slippery sliding surface and avalanches can travel farther and faster than you might expect.
Since mid-February, the snowpack is less reactive and terrifying avalanche activity has dropped off significantly. The majority of stability test are not popping off the column with excitement ending up in your lap. Despite our Persistent Slab avalanche problem trending down over the last week, looming weak layers have been cranky all season. Storm Slab avalanches triggered from deeper drifts could trigger deeply buried persistent weak layers. This cascade event would result in deeper failures and wider propagating contributing to a more deadly and destructive avalanche.
Initiating a failure in deeply buried weak layers below a stiff slab takes finding the right combination of depth and structure or the shallow spot on a slope. Stepping out into terrain near 35 degrees at higher elevations is like rolling the dice. Slopes harboring the right combination of depth and structure may tolerate multiple people traveling across or below without avalanching providing a false sense of security. During times like this, it does not matter how much you know about snow, avalanches, or how many years you have spent in the backcountry, recreating on steeper slopes is purely a game of chance.
Weak, fragile facets that formed in December keep rearing their ugly head and surprising observers with lingering sensitivity. A large remotely triggered avalanche outside of Lake City this week is a good reminder that weak snow lurking below can still fail from added weight of a rider or machine. Stubborn slabs may not offer clues of potential danger prior to failure and may even lure you further out onto a slope before breaking above and around you. You can reduce the chance of waking the monsters in the basement by sticking to lower angle slopes without overhead hazards or below treeline slopes.
If uncertainty surrounds your snowpack assessment or you are new to the backcountry, now is not the time to explore bigger, more complex terrain. If you are an old veteran, now is not the time to rely on what you have done in past years. Patience is a strong attribute and know that the snowpack will turn around, but it is not there yet.