THIS AVALANCHE FORECAST EXPIRED ON January 11, 2019 @ 7:00 am
Avalanche Forecast published on January 10, 2019 @ 7:00 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

The avalanche danger is MODERATE in near and above treeline areas with LOW danger below treeline. Some lingering wind slabs may still exist and persistent slabs have become unlikely but not impossible.

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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Some wind slabs may still linger on near treeline and above treeline NW-N-NE-E-SE aspects. In most cases, triggering one of these wind slabs should have become more difficult. However, some human-triggered wind slab avalanches may remain possible especially in cliffy areas, unsupported slopes, couloirs, and other complex or extreme terrain. Some of the cornices hanging above the slopes may also remain fragile.

Identify wind-loaded terrain features using clues like drifted snow, cornices above a slope, hollow-sounding firm snow, and other wind-created surface textures. This information can help manage the conditions and terrain to maintain appropriate safety margins around lingering wind slabs

Avalanche Problem 2: Persistent Slab
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As the storm snow and the older weak snow below it have gained strength, triggering a persistent slab has become unlikely. The weak layer remains (facets buried in the snowpack), but data seems to indicate that it has adjusted to the load above it in many places. Also, getting enough force through the strong storm snow layers to break this layer would be difficult. Still, this problem may not be impossible in an isolated area where conditions are just right.

Even though persistent slabs are unlikely, paying attention to whether or not this layer exists is a good plan. Use probing and snowpits to find and identify this layer. Areas where it is closer to the surface or where trigger points exist may represent some of those isolated areas where a surprise might still happen.

recent observations

* Yesterday observations on Wildflower Ridge (Donner Summit), Hidden Peak (West Shore), and Elephant's Hump (Carson Pass) that targeted the old weak snow below the recent storm snow indicated that it has adjusted to the load above it and would be difficult to get enough force through the strong layer of new snow to cause a failure in the old weak snow. 

* Observations on Wildflower Ridge found wind slabs and cornices but did not find lingering signs of instability associated with them. On the upper elevations of Rubicon Peak and Elephant's Hump active wind transport and loading continued during the day yesterday. 

Weather and CURRENT CONDITIONS
weather summary

Snow showers added another 3 to 7 inches of new snow in the last 24 hours according to remote sensors around the area. Most of the snow showers seem to have come to an end during the night and the weather has started to clear as a high-pressure ridge builds over the region. The forecast calls for partly cloudy skies, warmer temperatures, and lighter winds through Saturday.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 23 to 28 deg. F.
Max. temperature in the last 24 hours: 28 to 34 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 38 to 45 mph
Maximum wind gust in the last 24 hours: 88 mph
New snowfall in the last 24 hours: 3 to 7 inches
Total snow depth: 45 to 57 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Thursday Thursday Night Friday
Weather: Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Clear. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy then becoming mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%.
Temperatures: 37 to 42 deg. F. 21 to 26 deg. F. 37 to 42 deg. F.
Mid Slope Winds: Light winds. Light winds. East winds up to 10 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Thursday Thursday Night Friday
Weather: Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Clear. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy then becoming mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%.
Temperatures: 34 to 39 deg. F. 20 to 25 deg. F. 34 to 40 deg. F.
Ridge Top Winds: South 10 to 20 mph. Gusts up to 30 mph in the morning. South 10 to 15 mph. Gusts up to 25 mph after midnight. Southeast 15 to 20 mph with gusts to 35 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
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