THIS AVALANCHE FORECAST EXPIRED ON February 20, 2019 @ 6:59 am
Avalanche Forecast published on February 19, 2019 @ 6:59 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

MODERATE avalanche danger still exists at all elevations due to a combination of new and old wind slabs and some potential loose dry avalanches. Human triggered avalanches remain possible 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.

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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Wind-loading resulting from the NE winds over the last 24 hours has allowed new wind slabs to form on some SE-S-SW-W-NW aspects. Many of these should remain small, but some larger ones could have formed in the most heavily wind-loaded areas. In addition to these new wind slabs, some larger wind slabs and fragile cornices may still linger on some of the NW-N-NE-E-SE aspects that were loaded by previous SW winds and not too scoured by the NE winds. Overall expect variable wind affected conditions in near and above treeline terrain with human-triggered wind slabs possible on any aspect

Blowing snow, new and old cornices, wind pillows, scoured surfaces, and other wind created surface textures can help identify where wind slabs may exist. More sheltered terrain should hold softer snow conditions with fewer chances for finding fragile wind slabs or firm wind scoured surfaces.

Avalanche Problem 2: Loose Dry
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While storm slab avalanche activity has become unlikely, some human-triggered loose dry avalanche activity could remain possible on steep sheltered slopes where the snow remains cold and dry. These should remain small but could cause some problems in more complex or extreme terrain where getting knocked off balance could have serious consequences.

recent observations

* A small skier-triggered wind slab failed on a test slope on a SE aspect near the summit of Incline Lake Peak. Another party reported signs of reactive wind slabs in the Granite Chief Wilderness.

* Observers reported evidence of light NE wind scouring and transport near ridgelines on Donner Summit, on the East Shore, near Yuba Pass, in the Mt. Rose backcountry, and between Carson Pass and Ebbetts Pass. Large cornices also still lingered above slopes loaded by SW winds. Ski kicks could easily break these cornices in the Yuba Pass area.

* In more sheltered terrain in all of these areas, no signs of slab instabilities were reported and signs of settlement and consolidation existed. Some surface hoar had formed on open sheltered slopes in the Yuba Pass area, on Rubicon Peak, on Schallenberger Ridge, and in Johnson Canyon. 

* Some skier triggered loose dry sluffs occurred on steep terrain on Herlan Peak and in the Yuba Pass area.

* Observers reported small sun-crusts forming on sun-exposed southerly slopes in the Yuba Pass area and some sun affected snow on Herlan Peak by yesterday afternoon.  

Weather and CURRENT CONDITIONS
weather summary

The forecast calls for cold clear weather with NE winds today. By tonight another small storm approaching the area should bring an increase in cloud cover and cause the winds to shift back to the SW. This storm does not have much moisture associated with it but snow showers should begin tomorrow and continue through Thursday. Some areas could see 2 to 4 inches of snow tomorrow with additional snowfall Wednesday night into Thursday.  

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 3 to 8 deg. F.
Max. temperature in the last 24 hours: 15 to 25 deg. F.
Average wind direction during the last 24 hours: NE
Average wind speed during the last 24 hours: 25 to 35 mph
Maximum wind gust in the last 24 hours: 63 mph
New snowfall in the last 24 hours: trace to 0 inches
Total snow depth: 103 to 127 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Tuesday Tuesday Night Wednesday
Weather: Sunny. 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%. Mostly cloudy. Snow showers becoming likely by afternoon. Snow levels below 7000 feet. Chance of precipitation is 75%.
Temperatures: 26 to 32 deg. F. 10 to 18 deg. F. 21 to 26 deg. F.
Mid Slope Winds: East winds 10 to 15 mph becoming light in the afternoon. Light winds becoming southwest around 15 mph with gusts to 30 mph after midnight. Southwest around 15 mph with gusts to 30 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. 60% probability of 2 to 4 inches. 40% probability of up to 2 inches. | SWE = up to 0.15 inch.
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Sunny. 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%. Mostly cloudy. Snow showers becoming likely by afternoon. Snow levels below 7000 feet. Chance of precipitation is 75%.
Temperatures: 22 to 28 deg. F. 8 to 13 deg. F. 16 to 22 deg. F.
Ridge Top Winds: Northeast 15 to 25 mph with gusts to 50 mph. West 15 to 30 mph. Gusts up to 45 mph increasing to 55 mph after midnight. Southwest 15 to 30 mph. Gusts up to 60 mph decreasing to 45 mph in the afternoon.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. 60% probability of 2 to 4 inches. 40% probability of up to 2 inches. | SWE = up to 0.15 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