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 16, 2011:


January 16, 2011 at 8:00 am

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


Forecast Discussion:


The high pressure ridge lingering over the region will keep temperatures above normal with daytime highs climbing back into the mid to upper 40's and maybe even the low 50's above 7000 ft today. Cloud cover and westerly wind should increase today due to a storm system north of the forecast area. As this system moves east tomorrow, the winds should start to calm back down and the cloud cover should start to decrease.

Observations:

In the Mt. Rose area the rain crust extended up to 9400 ft on Mt Houghton. This 2 inch thick, firm, and supportable crust existed on all aspects up to that elevation. Above 9400 ft. a firm, 3-4 inch thick wind crust existed on the N-NE-E aspects. Hand pits indicated that this thin wind crust sat on top of a layer of softer snow and that it had not fully bonded to the snow below it (video). Observations from the Bear Valley area and from the Mt Rose area yesterday showed that melt-freeze conditions combined with the rain have formed an even thicker crust on the more southerly aspects. These southerly aspects did soften enough in in the Mt Rose area for a few small skier-triggered roller balls to occur (photo).

Avalanche Concerns:

Dangerous avalanche activity will remain unlikely today. Recent observations continue to show a well consolidated snowpack in most areas. Some small roller balls or wet, loose snow sluffs may occur on southerly, sun-exposed aspects; however, these should remain small due to the weak winter sun and more widespread cloud cover. Other very isolated pockets of weakness could still linger at the highest elevations (above 9500 ft) on wind-loaded slopes. These should also remain very small, very shallow, and difficult to trigger. Continue to travel with caution in the backcountry and evaluate slopes carefully before committing to them.


The bottom line:

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


Andy Anderson - Avalanche Forecaster, Tahoe National Forest


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

0600 temperature: 39 deg. F.
Max. temperature in the last 24 hours: 46 deg. F.
Average wind direction during the last 24 hours: West to Northwest
Average wind speed during the last 24 hours: 10-20 mph
Maximum wind gust in the last 24 hours: 39 mph
New snowfall in the last 24 hours: O inches
Total snow depth: 65-94 inches

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

For 7000-8000 ft:

  Sunday: Sunday Night: Monday:
Weather: Mostly cloudy Partly cloudy Partly cloudy
Temperatures: 46-53 deg. F. 33-38 deg. F. 45-52 deg. F.
Wind direction: West West West
Wind speed: 10-15 mph with gusts to 30 mph 10 mph with gusts to 25 mph 10 mph with gusts to 25 mph
Expected snowfall: O in. O in. O in.

For 8000-9000 ft:

  Sunday: Sunday Night: Monday:
Weather: Mostly cloudy Partly cloudy Partly cloudy
Temperatures: 39-46 deg. F. 31-37 deg. F. 39-45 deg. F.
Wind direction: West Northwest Northwest
Wind speed: 20-25 mph with gusts to 65 mph 20-35 mph with gusts to 70 mph 20-30 mph with gusts to 70 mph decreasing to 50 mph in the afternoon
Expected snowfall: O in. O in. O in.