THIS AVALANCHE FORECAST EXPIRED ON January 15, 2020 @ 6:59 am
Avalanche Forecast published on January 14, 2020 @ 6:59 am
Issued by Steve Reynaud - Tahoe National Forest

Light snow accumulations overnight with gale force winds will create wind drifted snow in near and above treeline areas.  Active weather will continue today with high winds throughout the forecast region.  MODERATE avalanche danger will exist in near and above treeline areas due to wind slabs, with LOW avalanche danger continuing in below treeline terrain.

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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Light amounts of additional snow overnight with gale force SW winds will form new wind slabs in near and above treeline areas.  These new wind slabs will be stacked on top of previous wind slabs that have formed over the last few days.  Wind gusts this morning have been reported over 100mph along the Sierra Crest.  These high winds could cause wind slabs to form further downslope off of ridges or in unusual locations.  Wind textured snow along with isolated wind slabs could even form in below treeline areas.

Active wind loading is expected to continue all day with blowing snow, building cornices, and wind scouring.  Avoid steep wind loaded terrain and areas below large cornices.  Firm wind scoured crusts will be present along exposed ridges and high points and could cause travel concerns.  Improved riding conditions are expected in wind protected below treeline terrain.    

recent observations
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Observations from Silver Peak (Pole Creek area) and Andesite Peak (Donner Summit area) came in yesterday.  Active light wind loading continued through the day at both locations.  Near treeline areas were wind scoured down to firm crusts, while more wind protected below treeline areas had wind pressed snow.  Cracking was limited at both areas with the newly formed wind slabs non-reactive.

Weak faceted snow around the Jan 4 rain crust was targeted for snowpack tests on Andesite Peak.  Snowpack tests did not show these weak layers to be as problematic as has been seen at other locations in the forecast region.

Weather and CURRENT CONDITIONS
weather summary

1 to 4'' of new snow has fallen overnight with gale force SW winds.  Wind speeds near 100mph have been recorded over the Sierra Crest with gusts up to 137mph!  Active weather will continue this morning with the possibility of 1 to 4'' of additional snow.  Snow showers will be convective and could set up in certain locations with more snow potential, with other areas receiving limited new snow.  Gale force SW winds will continue throughout the day.    A brief break is expected on Wednesday morning before a larger storm approaches our area late Wednesday night through Thursday.  This storm has the possibility for multiple feet of snow along the Sierra Crest with very high winds.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 18 to 26 deg. F.
Max. temperature: 21 to 33 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 40 to 80 mph
Maximum ridgetop wind gust: 137 mph
New snowfall: 1 to 4 inches
Total snow depth: 41 to 46 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy then becoming partly cloudy. Snow likely in the morning, then slight chance of snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 60%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%. Partly cloudy then becoming mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%.
Temperatures: 26 to 32. deg. F. 15 to 20. deg. F. 34 to 40. deg. F.
Mid Slope Winds: Southwest 30 to 45 mph decreasing to 20 to 30 mph in the afternoon. Gusts up to 80 mph. Southwest 15 to 25 mph. Gusts up to 55 mph decreasing to 40 mph after midnight. Light winds becoming southwest around 15 mph with gusts to 35 mph in the afternoon.
Expected snowfall: 60% probability of 1 to 4 inches. 40% probability of 3 to 5 inches. | SWE = up to 0.15 inch. No accumulation. 20% probability up to 1 inch. | SWE = none. No accumulation. | SWE = none.
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy then becoming partly cloudy. Snow likely in the morning, then slight chance of snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 55%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%. Partly cloudy then becoming mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%.
Temperatures: 22 to 28. deg. F. 13 to 18. deg. F. 30 to 36. deg. F.
Ridge Top Winds: Southwest 45 to 60 mph with gusts to 100 mph decreasing to 30 to 50 mph with gusts to 80 mph in the afternoon. Southwest 15 to 30 mph with gusts to 60 mph. Southwest 20 to 35 mph with gusts to 70 mph.
Expected snowfall: 70% probability of 1 to 4 inches. 30% probability of 4 to 6 inches. | SWE = up to 0.15 inch. No accumulation. 20% probability up to 1 inch. | 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