Central Sierra Nevada
Avalanche danger
Highlights
The shallow snow on cold, shady, upper-elevation slopes grows weaker each day. Avalanches will remain unlikely until new snow or rain adds weight to the snowpack despite this weakness. Those traveling on the snow will find a mix of conditions including firm icy surfaces.
Avalanche Discussion
While the last few weeks of warm dry weather have left bare ground on sunny slopes and at the lower elevations, a shallow snowpack does still exist on shaded upper elevation slopes. NW-N-NE aspects above 8000 to 8500 ft. hold enough snow to recreate on. That snowpack also remains mostly supportable. The supportability comes with a catch though since a mix of firm icy crusts and breakable crusts exist on the snow surface.
The northerly aspects where the snow lives stay mostly shady and cold this time of year despite the warmer air temperatures. That's why there is still snow on them. Weak indirect sun during the day combined with the longest nights of the year has allowed weak layers to form in the cold shallow snowpack. The once dense snow and solid rain crusts have deteriorated to a mix of weak sugary snow (facets) and eroding crusts in the mid and upper parts of the snowpack. Below these weakening layers, ice exists at the bottom of the snowpack in many areas.
For now, avalanche activity remains unlikely because little to no slab exists on top of the weak layers. When stormy weather decides to return to the area, the weak layers that have formed during this dry spell could lead to complicated avalanche problems. Mapping out the areas where these weak layers exist and monitoring them as they form will provide a key piece of information for decision-making after new snow buries them.
Recent Observations:
* 1 to 3 feet of snow exists on NW-N-NE aspects above about 8,000 ft. in many areas. The snow surface remains highly variable with a mix of firm icy crusts and breakable crusts in most places.
* Almost all SE-S-SW-W aspects are snow-free with continuous bare ground exposed. A few high elevation E-SE aspects hold snow cover.