Central Sierra Nevada
Avalanche danger
Highlights
Small slabs of wind drifted snow may still exist in isolated areas below ridges and gully features from the previous strong winds. These slabs are gaining strength, small in size, and pose limited risk to backcountry users. While avalanches are unlikely, they are not impossible in some of these isolated areas. Use normal caution while traveling in the backcountry.
Avalanche Discussion
Previous strong to gale force NE winds have formed some small wind slabs on SE-S-SW-W-NW aspects in near and above treeline areas. Yesterday, snow surface cracking and small wind slab avalanches were human triggered in these areas. These avalanches were all D1 in size, did not extend very far downslope, and posed limited risk to backcountry users. Most of these wind slabs will have gained strength yesterday with no additional wind loading occurring, but in isolated areas some small wind slabs may still be lingering. Use caution if traveling in these areas as even a small avalanche could have increased consequences in exposed terrain.
Partly cloudy skies, lighter winds, and slightly warmer temperatures are expected for today. Melt freeze crusts exist on most E-SE-S-SW-W aspects. Wind scoured surfaces exist in most all near and above treeline areas with soft snow on northerly aspects in wind protected below treeline terrain. Make a plan with your group before heading out into the backcountry that takes the current conditions into account. Look for changing conditions and signs of instability while moving through terrain. Continue to practice good backcountry travel skills during this period between storms.
Recent Observations:
- Small D1 wind slab avalanches were skier triggered yesterday on NW aspects in near treeline terrain in the Echo Summit area.
- Unconsolidated snow, unaffected by previous melt lingers on shaded northerly aspects in wind protected terrain below treeline.
- Melt-freeze crusts exist on most sun-exposed slopes.
- About one to two feet below the snow surface, older weak layers of buried surface hoar, near-surface facets, and/or graupel remain in some areas. Observations indicate a trend of increasing stability on these layers with improved bonding and decreasing reactivity in snowpit tests.