Southeast Mountains

Over the past two days, northwest winds have formed shallow wind slabs in wind-affected terrain at higher elevations. Slabs of drifted snow were easily triggered yesterday; they'll become stiffer and more difficult to manage today as you gain elevation.  You can find softer snow and safer riding in wind-protected slopes at lower elevations, where your primary concern is small gouging sluffs in very steep terrain on shady aspects.  At higher elevations, avoid consequential slopes where you see or feel thicker deposits of windblown snow.  

Monday's storm delivered a few inches of new snow to most of the forecast zone, and up to 12" in the Ruby Range and near Kebler Pass.   Increasing northwest winds, which peaked yesterday evening, have redistributed the snow into scattered wind slabs throughout the higher elevation terrain.  These new slabs are generally larger and more common in areas with the most new snow, though wind transport was visible across our entire forecast area yesterday.  Given the sustained winds and stronger speeds overnight, I expect at least some drifts are now hard slabs.  Hard slabs are typically more stubborn to triggers but can break above you and give less reliable feedback.  Even thin, hard slabs can knock you off your feet, something I wouldn't want to mess with above rocks, trees, or gullies.   You may have noticed that we expanded the wind slab rose to include windward aspects. This is due to a somewhat unique situation.  Wind drifting has consistently been out of the north and northwest since Monday's snowfall, so wind loading is more widespread on south to southeast aspects.  However, the storm interface is much weaker on the north half of the compass (remember the Axtell video), so any cross-drifted slabs that form on those old weak bed surfaces are expected to be more sensitive than slabs that formed over southerly sun crusts (see this observation). Slabs that get moving on these weaker aspects will grow larger as they entrain the old, faceted snow.  East aspects are the bullseye for the overlap between wind loading and fragile weak layers. However, there are usually isolated concave catchments and gullies on windward aspects (in this case, west to north) that can also catch drifting snow.  Reading surface textures will help you avoid the problem on those windward slopes: look for soft wind-protected snow or rippled texture (sastrugi) to indicate wind erosion and safer riding.  Wind slabs will look smooth and rounded, comparatively.  

There is still isolated potential for a small windslab in the upper snowpack to step down or for a human trigger to find the sweet spot on the rare slopes harboring problematic persistent slab structure.  Water weight from Monday's storm was minimal (.1" to .3" of SWE), but wind loading over the past 36 hours did add stress to the snowpack on heavily drifted terrain features, while eroding stress on most windward slopes. The persistent slab issue is most concerning near and above treeline in the Southeast Mountains where the shallower snowpack has produced a few avalanches breaking near the ground in the past week.