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.

Weak high pressure is building over the forecast area as yesterday's weather system moves off to the east. Ridgetop winds shifted from southwest to northeast late yesterday morning. Wind speeds have generally remained strong in speed over the past 24 hours. Moderate to strong northeast winds are forecast to gradually decrease as the day progresses, becoming light in speed tonight. Lingering cold air associated with yesterday's cold front passage will keep air temperatures near to below freezing today for most areas above 7,000'. A gradual warming trend is forecast over the next few days. A weather system passing to the north of the forecast area tomorrow will cause winds to shift to the west and increase to strong in speed.

Recent Observations:

Observations made yesterday on Becker Peak (Echo Summit area) and on Andesite Ridge (Donner Summit area) both revealed stable snowpack conditions. On Becker Peak, melt freeze crust on S-SW aspects prevented wind transport and subsequent wind slab formation Friday night (video, more info). On Andesite Ridge, wind slabs up to 8 inches deep were observed on N-NE-E aspects in near treeline terrain. The existence of a weak layer below these newly formed slabs was minimal, allowing for good bonding of the slabs to layers below and therefore good stability (video, more info). By mid day, ridgetop winds had shifted back to the NE and were lightly scouring any areas of newly formed wind slab and once again redistributing snow in near and above treeline areas. Warm snow surface conditions during the afternoon hours on SW-W aspects was noted to allow for good bonding of wind transported snow to the old snow surface yesterday afternoon.

Avalanche Problem #1: Wind Slabs

Strong to gale force winds of variable direction have occurred over the past 36 hours. Observations thus far have shown wind slabs have formed in some areas, but that associated instability has remained absent. On a regional scale, triggering a wind slab avalanche is unlikely today. That said, an isolated unstable wind slab may exist in recently wind loaded or cross loaded near treeline or above treeline terrain. Upper elevation complex or extreme terrain near the Sierra Crest is the most likely location for the existence of an unstable wind slab today.

A small amount of wet surface snow may form in wind protected areas at mid and lower elevations on southerly aspects today. While a few small roller balls may occur, wet snow avalanche activity is unlikely today.

The bottom line:

Avalanche danger is LOW for all elevations and aspects. Finding an isolated unstable wind slab is unlikely but not impossible today in near treeline or above treeline terrain. Normal caution is advised.

Brandon Schwartz - Avalanche Forecaster, Tahoe National Forest

Weather Observations from along the Sierra Crest between 8200 ft and 8800 ft:

0600 temperature:	9 to 16 deg. F.
Max. temperature in the last 24 hours:	20 to 29 deg. F.
Average wind direction during the last 24 hours:	Southwest shifting to northeast
Average wind speed during the last 24 hours:	SW 20 mph | NE 35 mph
Maximum wind gust in the last 24 hours:	SW 39 mph | NE 62 mph
New snowfall in the last 24 hours:	0 to trace inches
Total snow depth:	57 to 83 inches

Two-Day Mountain Weather Forecast - Produced in partnership with the Reno NWS

For 7000-8000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Sunny skies.	Partly cloudy skies.	Partly cloudy skies.
Temperatures:	27 to 35 deg. F.	25 to 30 deg. F.	35 to 42 deg. F.
Wind direction:	E	Variable	W
Wind speed:	15 to 25 mph with gusts to 40 mph, decreasing to 10 to 15 mph with gusts to 25 mph in the afternoon.	Light winds	10 to 20 mph with gusts to 30 mph.
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Sunday:	Sunday Night:	Monday:
Weather:	Sunny skies.	Partly cloudy skies.	Partly cloudy skies.
Temperatures:	25 to 32 deg. F.	23 to 30 deg. F.	30 to 37 deg. F.
Wind direction:	E	E shifting to W after midnight.	W
Wind speed:	40 to 55 mph with gusts to 80 mph, decreasing to 25 to 35 mph with gusts to 55 mph in the afternoon.	10 to 15 mph.	30 to 40 mph with gusts to 60 mph.
Expected snowfall:	O in.	O in.	O in.