Areas of loose wet snow avalanche problems are expected to form today on all aspects at all elevations as daytime warming melts surface snow on all aspects. Timing of when significant amounts of unstable surface wet snow form today could vary significantly around the forecast area due to the very wide range of air temperatures at the mid and upper elevations this morning. At any rate it will occur more quickly than yesterday. Human triggered avalanche activity will be possible this afternoon in all areas and could occur this morning is some of the warmer locations.
Pay attention to the amount and rate of surface wet snow formation. Avoid slopes over 35 degrees in slope angle where roller balls are occurring and/or where wet snow exceeds boot top height.
Observations made yesterday on the N side of Carson Pass and on Incline Lake Peak (Mount Rose area) revealed much slower than expected snow surface warming due to brisk NE to E winds. Areas of roller ball activity were noted on Incline Lake Peak on a SE aspect at and below 8,500' starting just before 1 pm. Newly formed wind slabs were small and did not extend very far down slope. Frozen snow surfaces ranging from wind packed to supportable or breakable melt-freeze crust existed in most areas near and above treeline up until at least mid day. Areas of unconsolidated snow lingered in wind protected areas on NW-N-NE aspects below treeline.
|0600 temperature:||30 to 42 deg. F.|
|Max. temperature in the last 24 hours:||35 to 43 deg. F.|
|Average wind direction during the last 24 hours:||E|
|Average wind speed during the last 24 hours:||30 mph|
|Maximum wind gust in the last 24 hours:||55 mph|
|New snowfall in the last 24 hours:||0 inches|
|Total snow depth:||121 to 175 inches|
Air temperature inversion conditions have a fairly wide range of air temperatures at the mid and upper elevations this morning. Remote weather stations between 7,700' and 8,700' are reporting anywhere from the low 30s to low 40s. High pressure will last through today for sunny to partly cloudy skies, light winds, and well above freezing maximum daytime air temperatures. Cloud cover and ridgetop winds will increase tonight ahead of an approaching cold front expected to pass though the region tomorrow morning. For Thursday, expect snow showers, strong to gale force ridgetop winds ranging from SW to NW, and the possibility of lightning.
This avalanche advisory is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This advisory covers the Central Sierra Nevada Mountains between Yuba Pass on the north and Ebbetts Pass on the south. Click here for a map of the forecast area. This advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.
For a recorded version of the Avalanche Advisory call (530) 587-3558 x258