The 142nd and final avalanche advisory for the 2017/2018 season was published on April 22nd. Thank you to all who have supported the avalanche center through volunteer hours, field observations, and financial support.
So far this fall, there have been three early season storms that have contributed to the basal layers for this season's snowpack. These occurred on Oct 25, Oct 31, and Nov 13. Significant melt occurred following the Oct snowfall events on all but shaded upper elevation northerly aspects. Snow depths ranging from 3 to 9 inches were observed on shaded N to NE aspects above 8,000' prior to the Nov 13 precipitation event. In some of these areas snow cover was very patchy melt-freeze snow while in the deeper areas it was fairly continuous facet layers. The Nov 13 event brought rain to most areas with an additional 1 to 3 inches of snow above 8,500' to 9,000'.
As daylight hours continue to trend shorter and air temperatures colder, snowfall that accumulates on N and NE aspects will likely remain through the winter. Aspects with more sun exposure may remain subject to melt. It will all depend on how the weather continues to progress.
At this time, any avalanche concerns remain focused on wind slabs. These wind slabs are most likely to form on wind loaded slopes directly below ridgelines and in gullies. Keep I mind that it does not take a thick slab to create an unforgiving avalanche. The shallow snowpack this time of year does not eliminate the risk of avalanches. It does increase the likelihood of impact with rocks and subsequent injury either while caught in a small avalanche or while attempting over snow travel.
The bigger picture concern at this time is the ongoing crust formation, faceting, and weakening of the slowly building snowpack. While not a major contributor to instability at this time, it may become a significant factor in the future if a major snowfall event is deposited on top of a weak faceted early season snowpack.
The non-profit arm of SAC remains hard at work. There are many great events currently on the calendar ranging from educational talks to ski movies to dinner events. Check the events page for more info.
There are also several excellent online avalanche education opportunities available to refresh and/or build your avalanche skills. Choose one from the drop down list under the "Education" tab at the top of this page.
Current remote weather station data as well as a general weather forecast for the area provided by the NWS can be found by clicking here.
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.
This website is owned and maintained by the non-profit arm of the Sierra Avalanche Center. Some of the content is updated by the USDA avalanche forecasters including the forecasts and some observational data. The USDA is not responsible for any advertising, fund-raising events/information, or sponsorship information, or other content not related to the forecasts and the data pertaining to the forecasts.