THIS AVALANCHE ADVISORY EXPIRED ON March 5, 2014 @ 6:41 am
Avalanche Advisory published on March 4, 2014 @ 6:41 am
Issued by Brandon Schwartz - Tahoe National Forest

Avalanche danger is MODERATE for all elevations and aspects on slopes 35 degrees and steeper due to a mix of wind slabs, loose wet snow, and wet slabs.

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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Pockets of wind slab that existed yesterday near treeline and above treeline on N-NE-E aspects received additional loading last night under new snowfall and moderate speed SW winds. Human triggered avalanches with slab thickness of 8 inches to 3 feet remain possible today.

Avalanche Problem 2: Loose Wet
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As the day progresses, daytime warming and occasional sun breaks will allow for wet loose avalanches to occur on all aspects and at nearly all elevations. Widespread roller ball activity is expected as new snow falls off of rocks and trees. In some areas these roller balls may progress to loose wet avalanches. Small natural and human triggered loose wet avalanches are possible today on slope 37 degrees and steeper.

Avalanche Problem 3: Wet Slab
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Areas that were either directly wind loaded or cross loaded last night and continue to hold an active weak layer may avalanche today under warming conditions. Small to medium size human triggered wet slab avalanches are possible today on NW-N-NE-E-SE aspects in wind effected near treeline and above treeline terrain. An isolated natural wet slab avalanche is unlikely but not impossible today in these same areas.

recent observations

Observations made yesterday on Incline Lake Peak (Mount Rose backcountry), Mt. Judah (Donner Summit area), Scout Peak (Echo Summit area), South Maggies (Desolation Wilderness area), and on Red Lake Peak (Carson Pass area) revealed a mix of unstable and stable snowpack conditions. On Incline Lake Peak and on Scout Peak, two very small slab avalanches were triggered. On Incline Peak, an intentional cornice collapse onto a test slope triggered a 14 inch deep wind slab that failed 10 feet wide on a near treeline NNE aspect at 9,500'. On Scout Peak a small snowboard triggered wet slab avalanche was triggered near treeline on an ENE aspect at 8,400'. The avalanche measured approximately 20 feet wide and had a 2 foot crown. Skiers descending South Maggies via NE aspect below treeline terrain reported triggering roller balls and pin wheels below 8,000'.

Observations made on Red Lake Peak and on Mt. Judah revealed widespread wet snow conditions with no evidence of instability observed from both formal and informal snowpack assessment.

Weather and CURRENT CONDITIONS
weather summary

The weather system that brought rain and snow to the forecast area over the past 24 hours is existing the region. After snow level rose to near 9,000' yesterday afternoon, snow level dropped overnight with 3 to 5 inches of new snow accumulation above 7,000'. After snow showers taper off this morning, partial clearing is expected today with mostly cloudy skies. Maximum daytime air temperatures above 7,000' are forecast to reach the low to mid 40s. Ridgetop winds remain out of the southwest this morning and are moderate in speed. Ridgetop winds are forecast to shift to the west and become light as the day progresses. There is a slight chance of light showers tonight and tomorrow before the next warm weather system arrives Wednesday night and Thursday.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 28 to 33 deg. F.
Max. temperature in the last 24 hours: 31 to 36 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 25 mph
Maximum wind gust in the last 24 hours: 47 mph
New snowfall in the last 24 hours: 3 to 5 inches
Total snow depth: 49 to 62 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy skies. Mostly cloudy skies with a slight chance of showers after midnight. Mostly cloudy skies becoming cloudy. A slight chance of rain in the morning. A chance of rain in the afternoon.
Temperatures: 40 to 46 deg. F. 26 to 33 deg. F. 42 to 49 deg. F.
Wind Direction: West Southwest Southwest
Wind Speed: Light winds. Light winds increasing to 10 to 15 mph with gusts to 25 mph after midnight. 15 to 20 mph with gusts to 30 mph, increasing to 25 to 30 mph with gusts to 45 mph in the afternoon.
Expected snowfall: 0 in. 0 to trace in. 0 in.
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy skies. Mostly cloudy skies with a slight chance of snow showers after midnight. Mostly cloudy skies becoming cloudy. A slight chance of rain and snow.
Temperatures: 39 to 46 deg. F. 25 to 32 deg. F. 36 to 43 deg. F.
Wind Direction: West Southeast shifting to southwest after midnight. Southwest
Wind Speed: 10 to 15 mph with gusts to 25 mph in the morning, becoming light. 10 to 15 mph shifting and increasing to 20 to 25 mph with gusts to 35 mph after midnight. 20 to 25 mph with gusts to 40 mph, increasing to 40 to 45 mph with gusts to 70 mph in the afternoon.
Expected snowfall: 0 in. 0 to trace in. 0 to trace 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.