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 January 31, 2013:

January 31, 2013 at 7:45 am

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

Forecast Discussion:

High pressure is in place over the forecast area. Sunny skies, light winds, and well above freezing maximum daytime air temperatures are forecast for the next few days. Ridgetop winds became light in speed yesterday and will remain light out of the east today. A short period of light southwest winds is expected tomorrow. Remote sensors are reporting air temperatures in the low to mid 30s this morning above 8,000'. Air temperatures are forecast to warm into the 40s today for most locations.

Recent Observations:

Observations made yesterday on Rose Knob Peak and on Tamarack Peak (Mount Rose area) revealed transitional snow surface conditions above 8,600'. In this area storm snow from late last week underwent the first significant post storm melt-freeze cycle yesterday on SE-S-SW aspects. Below 8,600', melt-freeze conditions were fairly well established due rain and recent warm air temperatures. On other aspects, the snow surface remained fairly cold with minimal melting on E and W aspects and no melting on NW-N-NE aspects. Shallow, small, stable wind slabs were observed near and along ridgelines above treeline in this area (photos, more info).

Observations made yesterday in the Deep Creek Drainage revealed that the snow surface was capped by a fairly supportable rain crust with less than 1 inch of recent new snow on top of the crust. Stable snowpack conditions with little to no warming were observed on northerly aspects in this area while southerly aspects were noted to hold very little snow (pit profile, photos, more info).

Avalanche Concerns:

Avalanche concerns for today are few. Wet surface snow will develop on SE-S-SW aspects in response to daytime warming. During the afternoon hours, small mostly inconsequential human triggered loose wet snow avalanches and roller balls may occur on SE-S-SW aspects on slopes 37 degrees and steeper. The small size of any loose wet snow avalanches is unlikely to pose a significant threat to backcountry travelers. Keep in mind that undesirable interaction with secondary terrain features such as cliffs, terrain traps, and trees can increase consequences significantly.

Small shallow wind slabs that formed on Sunday near and along ridgelines in above treeline areas have shown good stability over the past two days. Human triggering of a small shallow wind slab is unlikely today, but could theoretically occur. Above 8,600' in near or above treeline terrain on a SE-S-SW-W aspect, especially in an area of complex or extreme terrain is the most likely location. Maximum slab depth is unlikely to exceed 6 to 8 inches.

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: 30 to 37 deg. F.
Max. temperature in the last 24 hours: 37 to 45 deg. F.
Average wind direction during the last 24 hours: Northeast
Average wind speed during the last 24 hours: 19 mph
Maximum wind gust in the last 24 hours: 30 mph
New snowfall in the last 24 hours: O inches
Total snow depth: 57 to 83 inches

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

For 7000-8000 ft:

  Thursday: Thursday Night: Friday:
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 43 to 48 deg. F. 24 to 31 deg. F. 44 to 49 deg. F.
Wind direction: E Variable Variable
Wind speed: Around 10 mph in the morning, becoming light. Light winds Light winds
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Thursday: Thursday Night: Friday:
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 38 to 43 deg. F. 27 to 32 deg. F. 39 to 44 deg. F.
Wind direction: E SW Variable
Wind speed: 10 to 15 mph. Gusts up to 25 mph in the morning. 10 to 15 mph. Light winds
Expected snowfall: O in. O in. O in.