THIS AVALANCHE FORECAST EXPIRED ON January 7, 2021 @ 6:59 am
Avalanche Forecast published on January 6, 2021 @ 6:59 am
Issued by Steve Reynaud - Tahoe National Forest

Persistent slab and wind slab avalanche problems remain possible today.  MODERATE avalanche danger will exist at all elevations.  Unstable snow continues to exist in some areas of the forecast region.

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: Persistent Slab
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The weak layers in our snowpack have started to gain strength and adjust to the new snow load in many locations.  Unfortunately, the process of the Dec. 11 persistent weak layer improving and gaining strength is not the same at all locations.  While some areas are pointing to improving stability, others are showing active whumpfing and unstable snowpack test results.  2 large natural avalanches were reported that are thought to have occurred during the storm on Monday and potentially failed on the Dec. 11 PWL.  Many areas throughout the forecast region at mid to high elevations are developing deeper and stronger snowpacks.  Locations at lower elevations and in some parts of the southern forecast area have shallower and weaker snowpacks.  These areas that are still shallow with a well developed Dec. 11 weak layer remain the greatest concern.  This will make it more important to collect snowpack information from your specific area and to look for signs of instabilities.  

Could a large persistent slab avalanche still occur?  Yes.  Are conditions going to continue to improve over the days ahead?  Yes.  Conservative terrain choices are still recommended while traveling in the backcountry until this weak layer becomes unreactive.  Due to the large size, potential remote triggering, and unpredictable nature of persistent slabs, limiting exposure to this avalanche problem is warranted.              

Avalanche Problem 2: Wind Slab
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The wind slabs that formed during the Monday storm have continued to gain strength.  Increasing SW winds today will allow some additional snow transport and new wind slabs to develop on NW-N-NE-E-SE aspects in near and above treeline terrain.  New small wind slab development could develop where available snow for transport exists.

Look for blowing snow, new cornice development, and wind pillows as clues to where new wind slabs may be forming.  

recent observations
Submit Observations

*  Whumpfing, cracking, and unstable snowpack test results were reported from Blue Lakes to Indian Valley (Carson Pass to Ebbetts Pass area).  All of these signs of instabilities were occurring on the Dec 11 PWL.

*  Large natural avalanches were reported from Dicks Peak (Desolation Wilderness area), and Hawkins Peak (Carson Pass area).  Limited information in known at this time.

*  Mt. Judah (Donner Summit area), and Carpenter Ridge (Independence Lake area), and Waterhouse (Luther Pass area) all showed improving snowpack stability.

 

Weather and CURRENT CONDITIONS
weather summary

A weak weather system will pass by to our north this afternoon and evening bringing increasing winds and clouds with little to no precipitation.  Thursday night into Friday will be another chance of a small storm with 2 to 5''  possible, mostly favoring the northern part of the forecast region.  After that, high pressure builds into our area with sunny skies and warming temperatures for a potential extended dry period.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 23 to 29 deg. F.
Max. temperature: 29 to 37 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 15 to 20 mph
Maximum ridgetop wind gust: 36 mph
New snowfall: 0 inches
Total snow depth: 31 to 40 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 38 to 43. deg. F. 20 to 26. deg. F. 37 to 42. deg. F.
Mid Slope Winds: Light winds becoming southwest around 15 mph in the afternoon. Gusts up to 30 mph. Southwest around 15 mph with gusts to 30 mph in the evening becoming light. Light winds.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 34 to 39. deg. F. 19 to 25. deg. F. 33 to 39. deg. F.
Ridge Top Winds: Southwest 15 to 25 mph. Gusts up to 30 mph increasing to 45 mph in the afternoon. Southwest 15 to 30 mph with gusts to 50 mph decreasing to 15 to 20 mph with gusts to 45 mph after midnight. South around 15 mph. Gusts up to 35 mph in the afternoon.
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