THIS AVALANCHE FORECAST EXPIRED ON March 10, 2019 @ 7:59 am
Avalanche Forecast published on March 9, 2019 @ 6:59 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

The avalanche danger remains MODERATE in near and above treeline terrain due to the possibility of lingering wind slab avalanche problems. Human-triggered avalanches large enough to have consequences may remain possible in some areas. 

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
  • Size ?
    Historic
    Very Large
    Large
    Small

Leeward aspects (NW-N-NE-E-SE) in near and above treeline terrain still hold slabs of wind drifted snow. In most places, these wind slabs should be more difficult to trigger today, but the additional weight of a person might still release an avalanche in some areas. Complex or extreme terrain including couloirs, cliffy areas, unsupported slopes, and steep convex rollovers will be the most suspect. Wind slab avalanches could entrain enough snow to bury, injure, or kill a person. Large cornices exist along exposed ridgelines.

Today, areas with more avalanche concerns correspond to areas with more variable and challenging snow conditions. Seeking out more sheltered terrain will provide softer more consistent snow with fewer avalanche concerns. Use clues like cornices above a slope, blowing snow, drifted snow, and other wind created surface textures to identify where wind slabs and wind-affected snow may exist.

recent observations

Observations yesterday from the Mt. Rose backcountry, Yuba Pass, Donner Summit, Brockway Summit, and the Blue Lakes area all reported blowing snow and very large cornices along ridgelines.

On Incline Lake Peak yesterday, ski kicks triggered wind slab failures up to 12 inches deep on small test slopes. One observer also reported a small (4-6 inch deep) wind slab failure on Wildflower Ridge around 5 pm. On Yuba Pass, Andesite Peak, and Brockway Summit ski cuts on wind-loaded test slopes only produced minor cracking in shallow wind slabs and did not cause wind slab failures. 

Snowmobile slope cuts on some steep, more sheltered, N-facing test slopes in the Blue Lakes area did not produce signs of instability. Other observations from Yuba Pass, Donner Summit, Brockway Summit, and the Mt. Rose backcountry also did not see signs of instability in sheltered non-wind-affected terrain.

Sun crusts and wet snow were reported on southerly aspects on Brockway Summit and in the Blue Lakes area. 

Weather and CURRENT CONDITIONS
weather summary

Snow accumulation has remained limited over the last 24 hours with some exceptions in areas along the Sierra Crest reporting closer to 3 to 5 inches of new snow. A low-pressure system dropping south along the CA coast should bring more snow showers to the area this afternoon through tomorrow. Expect variable snow totals across the forecast area. The SW winds should start to decrease this afternoon and continue decreasing into tomorrow. Partly to mostly cloudy skies and colder temperatures in the forecast for today should limit any potential warming from the strong March sunshine. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 11 to 17 deg. F.
Max. temperature in the last 24 hours: 21 to 26 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 45 to 55 mph
Maximum wind gust in the last 24 hours: 87 mph
New snowfall in the last 24 hours: 1 to 5 inches
Total snow depth: 122 to 138 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Saturday Saturday Night Sunday
Weather: Partly cloudy then becoming mostly cloudy. Chance of snow showers through the day. Snow levels below 7000 feet. Chance of precipitation is 45%. Cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 50%. Cloudy. Snow showers likely. Snow levels below 7000 feet. Chance of precipitation is 60%.
Temperatures: 27 to 32 deg. F. 14 to 19 deg. F. 27 to 32 deg. F.
Mid Slope Winds: Southwest around 15 mph. Gusts up to 40 mph decreasing to 25 mph in the afternoon. Southwest around 15 mph with gusts to 25 mph in the evening becoming light. Light winds.
Expected snowfall: 100% probability up to 1 inch. | SWE = less than 0.10 inch. 70% probability of 1 to 3 inches. 30% probability of 3 to 5 inches. | SWE = up to 0.15 inch. 60% probability of 1 to 3 inches. 40% probability up to 1 inch. | SWE = less than 0.10 inch.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Partly cloudy then becoming mostly cloudy. Chance of snow showers through the day. Snow levels below 7000 feet. Chance of precipitation is 40%. Cloudy. Chance of snow showers. Snow levels below 7000 feet. Chance of precipitation is 50%. Cloudy. Snow showers likely. Snow levels below 7000 feet. Chance of precipitation is 60%.
Temperatures: 22 to 28 deg. F. 11 to 16 deg. F. 22 to 28 deg. F.
Ridge Top Winds: Southwest 15 to 30 mph with gusts to 55 mph decreasing to 15 to 20 mph with gusts to 40 mph in the afternoon. Southwest 15 to 20 mph with gusts to 35 mph. Light winds.
Expected snowfall: 100% probability up to 1 inch. | SWE = less than 0.10 inch. 70% probability of 1 to 3 inches. 30% probability of 3 to 5 inches. | SWE = up to 0.15 inch. 60% probability of 1 to 3 inches. 40% probability up to 1 inch. | SWE = less than 0.10 inch.
Disclaimer

This avalanche forecast is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This forecast 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 forecast applies only to backcountry areas outside established ski area boundaries. This forecast describes general avalanche conditions and local variations always occur. This forecast expires 24 hours after the posted time unless otherwise noted. The information in this forecast is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the avalanche forecast call (530) 587-3558 x258