THIS AVALANCHE ADVISORY EXPIRED ON April 19, 2017 @ 6:52 am
Avalanche Advisory published on April 18, 2017 @ 6:52 am
Issued by Brandon Schwartz - Tahoe National Forest

MODERATE avalanche danger continues at all elevations due to ongoing wind slab and loose wet avalanche problems. Human triggered avalanches are possible today. Natural avalanches are unlikely but not impossible in isolated areas. Identify and avoid areas of potential wind slab and loose wet avalanche problems. A small chance exists that a rapid warming situation could occur this afternoon.

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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Additional wind and snow above 7,500' last night is expected to have created additional wind slab avalanche problems above 7,500'. The vast majority of wind slabs are expected near treeline and above treeline on NW-N-NE-E-SE aspects. Avalanche size could be large enough to bury or injure a person.

Identify and avoid areas of recent wind slab formation often found below or adjacent to cornice formations and wind pillows.

Avalanche Problem 2: Loose Wet
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Rain on snow has created wet surface snow on all aspects below 7,000' to 7,500'. Loose wet avalanche problems remain possible in these areas. Avalanche size could range from small to large enough to bury or injure a person, especially if a terrain trap is involved. In the unlikely event that significant sun breaks occur this afternoon, loose wet avalanche problems could extend to higher elevations.

Avoid travel on or below steep slopes where a few inches or more of wet surface snow exists.

Avalanche Problem 3: Wet Slab
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There is a small chance that skies could clear enough this afternoon to allow for sufficient incoming solar radiation to create a rapid warming situation. In the unlikely event that this occurs, wet slab avalanche problems could develop in sun exposed areas on any aspect that holds a few inches or more of new snow. Be cognizant of any sun breaks that occur today, especially if they last longer than a few minutes. It's getting to be mid to late April and solar radiation is much more intense and influential on snowpack instability than it was during February and March.

recent observations

Observations made yesterday on Tamarack Peak (Mount Rose area) revealed light rain as high as 9,000' and moderate snow showers as low as 8,500'. Dense new snow in wind loaded areas showed some indications of a difficult to trigger wind slab avalanche problem.

Weather and CURRENT CONDITIONS
weather summary

A weather disturbance passing through the forecast area has rain and snow ongoing this morning. Snow levels have been in the 7,500' to 8,000' range overnight. Snow levels are forecast to drop to around 7,000' this afternoon. Short lived but potentially intense convective showers are possible this afternoon. Skies are expected to clear a bit this evening through tomorrow between the departing current weather system and the next weather system expected to arrive late tomorrow night. Ridgetop winds out of the SW are decreasing in speed this morning, moderate to strong gusts remain possible today. Light winds tomorrow morning will give way to increasing SW winds tomorrow afternoon ahead of the next weather system.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 29 to 33 deg. F.
Max. temperature in the last 24 hours: 34 to 41 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 45 mph
Maximum wind gust in the last 24 hours: 97 mph
New snowfall in the last 24 hours: 3 to 6 inches
Total snow depth: 131 to 198 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Tuesday Tuesday Night Wednesday
Weather: Cloudy skies with rain and snow in the morning. A chance of rain and snow in the afternoon. Partly cloudy skies. Isolated rain and snow showers in the evening. Partly cloudy skies.
Temperatures: 34 to 44 deg. F. 23 to 29 deg. F. 44 to 50 deg. F.
Wind Direction: SW SW SW
Wind Speed: 15 to 20 mph with gusts to 40 mph. 10 to 15 mph with gusts to 35 mph in the evening, becoming light. Light winds becoming 15 to 25 mph with gusts to 45 mph in the afternoon.
Expected snowfall: Up to 2 in. 0 to trace in. 0 in.
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Cloudy skies with rain and snow in the morning. A chance of rain and snow in the afternoon. Partly cloudy skies. Isolated snow showers in the evening. Partly cloudy skies.
Temperatures: 28 to 38 deg. F. 19 to 24 deg. F. 35 to 45 deg. F.
Wind Direction: SW SW SW
Wind Speed: 20 to 35 mph. Gusts to 75 mph decreasing to 60 mph in the afternoon. 20 to 30 mph. Gusts to 60 mph decreasing to 50 mph after midnight. 20 to 30 mph. Gusts to 55 mph increasing to 75 mph in the afternoon.
Expected snowfall: 1 to 2 in. 0 to trace 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