THIS AVALANCHE FORECAST EXPIRED ON February 27, 2019 @ 7:00 am
Avalanche Forecast published on February 26, 2019 @ 7:00 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

Gale force winds and periods of high-intensity snowfall (especially tonight) will keep HIGH avalanche danger in near and above treeline terrain. The avalanche danger is CONSIDERABLE in below treeline terrain. Avalanche activity is very likely. Travel in avalanche terrain is not recommended. 

4. High

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Above Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

4. High

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Near Treeline
Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
Avalanche Problem 1: Wind Slab
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The wind slabs that started forming yesterday will become larger and more widespread today due to continued gale force winds and additional snow accumulation. NW-N-NE-E-SE aspects in near and above treeline terrain should hold the largest of these wind slabs but some could also exist in exposed below treeline areas as well. Wind slab avalanches will be likely today and should become very likely as the storm reintensifies tonight. Some wind slabs could start in traditional start zones near ridgelines and run into below treeline terrain.

Avalanche Problem 2: Storm Slab
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Changing conditions during the storm and periods of rapid snow accumulation mean that human-triggered storm slab avalanches will also be likely today and tonight. A chance for rising temperatures today could also exacerbate the storm slab problem. Storm slabs could exist on any steep slopes and could be large enough to bury or injure a person especially in areas that have received the most storm snow. In areas where less new snow exists storm slabs may be less prevalent.

recent observations

* Observers reported strong winds and blowing snow along the Sierra Crest and in the Mt. Rose backcountry yesterday.

* Some small fragile wind slabs had started to form in the Deep Creek area and on parts of Fireplug. 

* One party on the west shore noted a recent wind slab avalanche on Peak 9269. 

* Observations from Deep Creek, Fireplug, and the West Shore did not reveal signs of instability other than the newly forming wind slabs

Weather and CURRENT CONDITIONS
weather summary

A winter storm has brought gale force winds and heavy snowfall to the region. This storm system has had more impacts in areas north of Emerald Bay with sensors in the northern part of the forecast area reporting 14 to 18 inches of new snow since yesterday afternoon. The southern part of the forecast area received 10 to 12 inches of new snow. Snowfall amounts for today were reduced some in this morning's forecast. The storm should intensify again tonight with snowfall rates reaching 2 to 3 inches per hour in some areas. The forecast calls for a small lull in the storm tomorrow before another wave moves through the area on Thursday. Gale force SW winds should continue throughout the storm. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 22 to 28 deg. F.
Max. temperature in the last 24 hours: 25 to 34 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 60 to 70 mph
Maximum wind gust in the last 24 hours: 122 mph
New snowfall in the last 24 hours: North of Emerald Bay: 14 to 18 inches | South of Emerald Bay: 10 to 12 inches
Total snow depth: 104 to 149 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. Snow. Snow levels below 7000 feet. Chance of precipitation is 100%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 100%. Mostly cloudy. Snow in the morning, then snow likely in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 90%.
Temperatures: 34 to 39 deg. F. 29 to 34 deg. F. 36 to 41 deg. F.
Mid Slope Winds: South to southwest 20 to 40 mph with gusts to 60 mph. South to southwest 25 to 40 mph with gusts to 60 mph. Southwest 20 to 30 mph with gusts to 60 mph.
Expected snowfall: 70% probability of 4 to 8 inches. 30% probability of 8 to 12 inches. | SWE = up to 0.60 inch. 80% probability of 9 to 16 inches. 20% probability of 16 to 20 inches. | SWE = 0.80-1.50 inches. 80% probability of 2 to 5 inches. 20% probability of 5 to 8 inches. | SWE = up to 0.50 inch.
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 100%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 100%. Mostly cloudy. Snow in the morning, then snow likely in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 90%.
Temperatures: 31 to 37 deg. F. 26 to 31 deg. F. 32 to 38 deg. F.
Ridge Top Winds: Southwest 50 to 75 mph with gusts to 115 mph. Southwest 50 to 70 mph with gusts to 115 mph. Southwest 35 to 55 mph. Gusts up to 115 mph decreasing to 85 mph in the afternoon.
Expected snowfall: 70% probability of 5 to 10 inches. 30% probability of 10 to 12 inches. | SWE = 0.40-0.65 inch. 70% probability of 12 to 20 inches. 30% probability of 20 to 28 inches. | SWE = 1.00-2.00 inches. 80% probability of 3 to 6 inches. 20% probability of 6 to 10 inches. | SWE = 0.25-0.50 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