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 Avalanche Advisory was published on February 13, 2013:


February 13, 2013 at 7:31 am

Avalanche danger is LOW for all elevations and aspects. Normal caution is advised.


Forecast Discussion:


High pressure continues to slowly build over the forecast area. Sunny skies, above freezing air temperatures, and light winds are forecast for today. Remote sensors are reporting air temperatures above 8,000' in the low 20s to low 30s this morning. Maximum daytime air temperatures are forecast to reach into the upper 30s to mid 40s today above 8,000'. A weather disturbance passing to the east of the forecast area tonight and tomorrow will give a slight increase to northeast winds tonight and cool air temperatures at the upper elevations for tomorrow by about 5 degrees.

Recent Observations:

Observations made yesterday on Becker Peak (Echo Summit area) revealed small, shallow, stable wind slabs on SE-S-SW aspects along the ridgetop. A variety of formal and informal tests on these wind slabs produced no signs of instability (photos, more info). This matched well with observations from Monday targeting recently formed wind slabs along Carpenter Ridge (Independence Lake area) (photos, more info).

Snowpit data collected on the north side of Becker Peak matched well with other recent observations on northerly aspects around the forecast area. Near surface and near crust faceting processes continue to act on the the top 1 foot or so of the snowpack in these areas. On Becker Peak, less faceting was noted as compared to other locations around the forecast area. Up to a couple inches or so of recent storm snow exists on top of mostly supportable rain crust with softer faceted snow below. With no significant load above these weak layers, the snowpack is currently stable in these areas (pit profile, more info).

Avalanche Concerns:

Avalanche concerns for today are few. As air temperatures continue to warm, some natural or human triggered roller ball activity is possible. With very little recent storm snow present on the vast majority of E-SE-S-SW-W aspects, no significant amount of wet snow instability is expected. Winds slabs that formed under NE winds on Sunday night have shown very good stability over the past two days. Human triggering of shallow wind slabs that exist in near and above treeline terrain on SE-S-SW-W-NW aspects is unlikely today.


The bottom line:

Avalanche danger is 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: 22 to 31 deg. F.
Max. temperature in the last 24 hours: 35 to 44 deg. F.
Average wind direction during the last 24 hours: Northeast
Average wind speed during the last 24 hours: 17 mph
Maximum wind gust in the last 24 hours: 27 mph
New snowfall in the last 24 hours: O inches
Total snow depth: 56 to 79 inches

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

For 7000-8000 ft:

  Wednesday: Wednesday Night: Thursday:
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 37 to 44 deg. F. 22 to 30 deg. F. 38 to 45 deg. F.
Wind direction: N NE E
Wind speed: Light winds Light winds increasing to 10 to 15 mph after midnight. 10 to 15 mph.
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Wednesday: Wednesday Night: Thursday:
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 38 to 44 deg. F. 22 to 28 deg. F. 33 to 40 deg. F.
Wind direction: N NE E
Wind speed: 10 to 15 mph with gusts to 25 mph in the morning, becoming light. 10 to 15 mph. Gusts to 25 mph after midnight. 10 to 15 mph. Gusts to 25 mph in the morning.
Expected snowfall: O in. O in. O in.