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.

High pressure remains in control of the local weather. Cold air is in place over the forecast area this morning. Remote sensors are reporting air temperatures in the upper teens and low 20s above 6,500' at 6am. Colder air has settled into many of the mountain valleys below 6,500'. Maximum daytime air temperatures are expected to reach the low 30s to low 40s above 7,000' today. Calm winds overnight are forecast to increase to light to moderate in speed out of the east this morning in response to low pressure over the central US. Similar weather conditions are forecast for tomorrow.

Observations:

Observations made yesterday on Incline Lake Peak (Mount Rose area) revealed a new layer of well developed low density facets near the base of the snowpack. These facets were noted to have formed just above the basal ice layer on a north aspect at 9,400'. Snowpit data indicated that this layer remains stable at this time, but is likely developing in the direction of eventual instability (pit profile, more info). This puts this layer on the list of things to watch, but snowpack failure on this layer is unlikely at this time. On Jake's Peak (West Shore Tahoe area) more evidence of stable conditions on N-NE-E aspects, similar to other recent observations from across the forecast area were observed. The lower and middle portions of the snowpack remain quite strong and anchored while near surface faceting processes are weakening the upper portion of the snowpack (pit profile, more info). The rain crust that formed after the January 26 rain event exists at or near the snow surface and continues to facet, becoming increasingly brittle (photos, pit profile, more info). With a few areas of exception, the up to 2 inches of new snow from Wednesday have been well scoured off of N-NE-E aspects in near and above treeline areas by recent NW and NE winds. A brittle rain crust covers the snow surface on N-NE-E aspects while redistributed snow exists in patches on S-SW-W aspects. There has been no evidence of unstable slab formation in wind loaded areas. Observations over the past week have noted fairly well established melt-freeze conditions on SE-S-SW aspects.

Avalanche Concerns:

Near to above freezing air temperatures today and light to moderate east winds are not expected to change the snowpack conditions that existed yesterday on N-NE-E aspects.  The overall stable snowpack on northerly aspects is expected to keep avalanche activity unlikely today due to the lack of unstable slabs overlying the weaker faceted snow and rain crust that exist both near the top and bottom of the snowpack. The above freezing air temperatures will allow for some wet surface snow to form today on SE-S-SW aspects. Some upper elevation southerly aspects may remain frozen all day. Small amounts of roller ball activity may occur today in the remaining areas on SE-S-SW aspects where recent new snow has yet to under go its first melt-freeze cycle. Any wet snow surface instability is expected to be minimal and not pose a significant threat to backcountry travelers.

 

The bottom line:

Avalanche danger remains LOW for all elevations and aspects. 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:	18 to 19 deg. F.
Max. temperature in the last 24 hours:	28 to 40 deg. F.
Average wind direction during the last 24 hours:	East
Average wind speed during the last 24 hours:	12 mph
Maximum wind gust in the last 24 hours:	31 mph
New snowfall in the last 24 hours:	O inches
Total snow depth:	19 to 36 inches

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

For 7000-8000 ft:
	Saturday:	Saturday Night:	Sunday:
Weather:	Sunny skies.	Clear skies.	Sunny skies.
Temperatures:	36 to 43 deg. F.	15 to 25 deg. F.	36 to 43 deg. F.
Wind direction:	E	E	E
Wind speed:	10 to 20 mph. Gusts to 30 mph in the morning.	10 to 20 mph with gusts to 30 mph.	10 to 15 mph. Gusts to 25 mph in the morning.
Expected snowfall:	O in.	O in.	O in.
For 8000-9000 ft:
	Saturday:	Saturday Night:	Sunday:
Weather:	Sunny skies.	Clear skies.	Sunny skies.
Temperatures:	32 to 42 deg. F.	20 to 30 deg. F.	32 to 42 deg. F.
Wind direction:	E	E	E
Wind speed:	10 to 20 mph. Gusts to 30 mph in the morning.	10 to 20 mph with gusts to 30 mph.	10 to 15 mph. Gusts to 25 mph in the morning.
Expected snowfall:	O in.	O in.	O in.