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.
Snowfall from the October 28 storm event lingers on N and NE aspects. Most other aspects have melted out, exposing bare ground in the majority of areas. The general trend in snowpack structure observed thus far on mid and upper elevation N and NE aspects is fairly thin and weak melt-freeze crust on top of facets down to ground level. Overall snowpack height ranges from 6 to 10 inches deep in many of the areas that have continuous snow cover. Check out the Observations Page for additional details.
As additional weather systems affect the forecast area, here are some ideas to think about:
Areas directly below ridgelines as well as gully features that are subject to wind loading may exhibit slab formation despite a shallow snowpack. Wind loading can increase snow deposition rates by 2 to 10 times the rate that snow is falling from the sky. This rapid loading can create enough snowpack instability for an avalanche to occur, despite only a few inches of snow on the ground in wind protected areas. Make constant observations as you travel, looking for indications of current or recent snowpack instability. The best indicator is recent avalanche activity. Other signs of snowpack instability including wind loading, collapse, audible whumpfing sounds, shooting cracks, and/or test slope failure are excellent indications that the snowpack in the immediate area is unstable. When signs of an unstable snowpack exist, the only addition factors needed for avalanche to occur are a slope steeper than 30 degrees and a trigger.
If headed out to travel in or below avalanche terrain, each person should travel with avalanche rescue equipment including a transceiver, probe, and shovel with which they are well practiced. Allow only one person at a time to travel on or below slopes that are steeper than 30 degrees. Many hazards such as rocks, down trees, and stumps are often hidden just beneath the snow surface. Travel cautiously and slowly as it is a very long winter after getting hurt this time of year. Often the best way to satiate early season excitement is to put fresh batteries in avalanche transceivers and practice rescue skills.
Check out the avalanche tutorials specifically designed for skiers and snowmobilers at the Forest Service National Avalanche Center web site.
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.
Please note: If you are intending to travel within the boundaries of a ski area that is not yet open for the season, no avalanche mitigation measures exist at this time. Please treat any closed ski area as the backcountry terrain and snowpack that it currently is. Respect any closure signs that may be in place at the parking lot or base area. Carry proper backcountry equipment and avalanche rescue equipment. Expose only one person at a time to avalanche terrain (which is often widespread and complex within a ski area). Do not traverse above others. Things may look the same and seem very familiar to an operating ski area, but from a safety standpoint, right now the risk is significantly higher.
The long term forecast remains mostly dry. Occasional troughs and cold fronts are expected to pass through the area bringing occasional periods of increased winds, colder air temperatures, and possibly some light snowfall. Any major storms are on the far end of the horizon at this time, possibly closer to Thanksgiving week. That said, weather models do not have the best verification record during October and November due to the seasonal change. Keep you fingers crossed for a significant storm system to track through our area in the coming weeks.
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.