THIS AVALANCHE ADVISORY EXPIRED ON March 11, 2014 @ 6:59 am
Avalanche Advisory published on March 10, 2014 @ 6:59 am
Issued by Brandon Schwartz - Tahoe National Forest

Pockets of MODERATE avalanche danger are expected to form as the day progresses near and above treeline on N-NE-E aspects on slopes 35 degrees and steeper due to building wind slabs. Avalanche danger is LOW for all other elevations and aspects. Isolated areas of unstable loose wet snow are unlikely but not impossible today.

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.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    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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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
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    Historic
    Very Large
    Large
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Areas of small wind slab are expected to have begun to build along the Sierra Crest above 7,000' to 8,000' in areas where snowfall occurred last night. With a few more inches of new snow expected to add to wind slab development during cold front passage later today, isolated areas of instability are expected to form near and above treeline on N-NE-E aspects. Wind slabs are expected to be less than 1 foot deep and are not expected to extend very far down slope. If new snow amounts exceed forecast expectations, areas of larger wind slabs will form.

advisory discussion

Areas of wet snow will exist this morning after rain on snow last night. Decreasing air temperatures are expected to keep any areas of loose wet snow instability to a minimum today as free water production ceases and snow surface refreeze begins to occur.

recent observations

Observations made yesterday on Jake's Peak (West Shore Tahoe area) and on Castle Peak (Donner Summit area) revealed widespread wet snow with conditions remaining supportable above 7,500' into the afternoon hours. Recent observations from around the forecast area indicated that the snowpack below 8,500' was in good condition to handle last night's rain with free water drainage from the snowpack well established.

Weather and CURRENT CONDITIONS
weather summary

A warm pacific storm system is currently impacting the region. Thus far, precipitation has been focused on the west side of the Sierra Crest over the northern 2/3rds of the forecast area. Precipitation is expected to extend to the rest of the forecast area as the day progresses. Snow levels started out last night around 9,700' and have fallen to around 7,000' this morning. New snow amount range from a trace to 2 inches. Wind speeds are increasing this morning as a cold front approaches the area. Ridgetop gusts have reached 100 mph this morning. As the cold front passes through during the late morning to early afternoon hours snow levels will further drop to 6,000' to 6,500'. A short burst of snowfall is forecast to accompany frontal passage bringing 1 to 3 inches of new snow above 7,000'. It is possible that new snow amounts later today could exceed forecast expectations.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 30 to 32 deg. F.
Max. temperature in the last 24 hours: 42 to 49 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 55 mph
Maximum wind gust in the last 24 hours: 100 mph
New snowfall in the last 24 hours: trace to 2 inches
Total snow depth: 43 to 53 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Cloudy skies becoming mostly cloudy. Snow in the morning. Scattered snow showers in the afternoon. Partly cloudy skies, becoming clear. Sunny skies.
Temperatures: 35 to 43 deg. F. 20 to 24 deg. F. 30 to 38 deg. F.
Wind Direction: Southwest North shifting to northeast Northeast
Wind Speed: 25 to 35 mph with gusts to 55 mph. 25 to 30 mph with gusts to 45 mph, shifting and decreasing to 10 to 15 mph with gusts to 25 mph after midnight. 15 to 20 mph with gusts to 35 mph, increasing to 20 to 30 mph with gusts to 40 mph in the afternoon.
Expected snowfall: Up to 2 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Cloudy skies becoming mostly cloudy. Snow in the morning. Scattered snow showers in the afternoon. Partly cloudy skies, becoming clear. Sunny skies.
Temperatures: 27 to 37 deg. F. 20 to 24 deg. F. 26 to 32 deg. F.
Wind Direction: Southwest shifting to west North shifting to northeast Northeast
Wind Speed: 55 to 60 mph with gusts to 90 mph, shifting and decreasing to 45 to 50 mph with gusts to 75 mph in the afternoon. 40 to 45 mph with gusts to 70 mph, shifting and decreasing to 20 to 25 mph with gusts to 40 mph after midnight. 25 to 35 mph with gusts to 50 mph.
Expected snowfall: Up to 3 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.