THIS AVALANCHE ADVISORY EXPIRED ON December 4, 2016 @ 6:58 am
Avalanche Advisory published on December 3, 2016 @ 6:58 am
Issued by Andy Anderson - Tahoe National Forest

The avalanche danger remains LOW for all aspects and elevations. LOW danger does not mean "no danger" and small avalanches could still occur in isolated areas or extreme terrain. Practice safe backcountry travel habits like moving one at a time from safe zone to safe zone to reduce your risk while traveling through avalanche terrain. Early season conditions exist with numerous exposed and shallowly buried obstacles in most areas.

1. Low

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Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Normal Caution
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Triggering an avalanche remains unlikely today, but unlikely does not mean impossible. Some unstable snow could still exist on isolated terrain features especially on leeward aspects where wind slabs may exist. Still, small avalanches can have big consequences especially when the snowpack remains shallow. Even though the avalanche danger remains LOW practicing safe back-country travel habits represents a great idea. Make a travel plan, discuss it with your group, and share it with someone who will not be on your tour. Continue to evaluate the snowpack and terrain and watch out for those isolated terrain features where unstable snow may remain. When moving into or through potential avalanche terrain, only expose 1 member of your group at a time. Identify safe zones out of avalanche terrain and re-group in those areas. Practicing these techniques now will make them habits that will serve you well on days when increased avalanche danger exists.

In addition to LOW avalanche danger, a LOW-tide snowpack also exists and while LOW avalanche danger means less avalanche hazard, the shallow snowpack means more exposed and shallowly buried obstacles to hit. Collisions with these exposed or barely covered rocks, logs, stumps, trees, and other hard immovable objects can break equipment and people. Enjoy the snow, but be careful so that that enjoyment will last all season long.

advisory discussion

The deepest and most usable snowpack within the forecast area exists along the northern portion of the Sierra Crest. Along the Sierra Crest south of Tahoe City, snowpack depths decrease, even at the highest elevations. Recent storms have added to the snowpack in all areas but many rocks and shallowly buried obstacles still exist. The Mount Rose area in the NE portion of the forecast area has decent snow cover, but impact with rocks remains likely at the lower elevations in this area as well.

We greatly appreciate all of the recent avalanche and snowpack observations submitted by local users. This data helps us craft better advisories. Please continue to submit observations through the "submit observations" buttons found throughout this website. Remember any information you have can help. Simple weather and snowpack observations like how deep do you sink in the snow,  have you seen any avalanches or signs of instability, did you see snow blowing at the ridgelines are all helpful. Of course, we will take more detailed observations like snowpit data, videos, or photos as well. 

recent observations

Yesterday observations from Andesite Ridge showed significant wind scouring and wind affected snow on exposed near and above treeline terrain as well as in more sheltered below treeline terrain due to the gale force NE and E winds. Despite the strong winds wind transport and wind slab formation remained limited and the wind slabs noted on the leeward aspects remained small and did not extend very far downslope. Across the Lake on Tamarack Peak the NE and E winds remained weaker and only scoured exposed near and above treeline slopes. In sheltered below treeline areas, the snow remained soft and unconsolidated. Snowpit tests in both these areas did not reveal any signs of instability.

Snowpit data on Tamarack Peak still identified a persistent weak layer buried in the snowpack, but tests on this layer indicated triggering it has become unlikley. While it may not represent a current avalanche problem any more it still warrants observations to see if it could re-awaken during a future loading event. This persistent weak layer has been found on N aspects along the northern portion of the Sierra Crest above 8300' and in the Mt. Rose area above 9300'. There have been no avalanches associated with this layer.

Weather and CURRENT CONDITIONS
weather summary

North to northeast winds should continue today as a high-pressure ridge builds over the region. While these winds may not reach the speeds that they did yesterday along the Sierra Crest, the forecast still calls for speeds of 20 to 30 mph with gusts to 65 mph this morning. As the ridge establishes itself over the region the winds should begin to decrease. By tomorrow the winds should shift back to the southwest due to a low-pressure moving into NV. Temperatures have already started to warm at the upper elevations with many sensors above 8000 ft. reporting temperatures in the 30's this morning. Valley temperatures remain colder since the colder air remains trapped in the valleys. Temperatures should continue the warming trend tomorrow with daytime highs climbing another 10 degrees into the upper 30's to upper 40's above 7000 ft.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 30 to 36 deg. F.
Max. temperature in the last 24 hours: 31 to 36 deg. F.
Average wind direction during the last 24 hours: East and northeast
Average wind speed during the last 24 hours: During the day yesterday: 50 to 60 mph | Overnight: 35 mph mph
Maximum wind gust in the last 24 hours: 101 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 12 to 21 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Saturday Saturday Night Sunday
Weather: Sunny Clear Partly Cloudy
Temperatures: 32 to 37 deg. F. 21 to 29 deg. F. 42 to 48 deg. F.
Wind Direction: North Northwest Northwest shifting to the southwest in the afternoon
Wind Speed: 10 to 20 mph with gusts to 35 mph decreasing to 25 mph in the afternoon 10 mph 10 to 15 mph increasing to 15 to 25 mph with gusts to 40 mph in the afternoon
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Sunny Clear Partly Cloudy
Temperatures: 30 to 36 deg. F. 24 to 29 deg. F. 39 to 47 deg. F.
Wind Direction: Northeast Northeast shifting to northwest after midnight Northwest shifting to the southwest in the afternoon
Wind Speed: 20 to 30 mph with gusts to 65 mph decreasing to 15 to 20 mph with gusts to 50 mph in the afternoon 15 to 20 mph with gusts to 40 mph decreasing to gusts to 30 mph after midnight 15 to 25 mph with gusts to 35 mph increasing to gusts to 50 mph in the afternoon
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer

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.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258