THIS AVALANCHE FORECAST EXPIRED ON March 15, 2020 @ 7:00 am
Avalanche Forecast published on March 14, 2020 @ 7:00 am
Issued by Steve Reynaud - Tahoe National Forest

A strong winter storm has started to impact our area with high winds and heavy snow expected.  Wind slab and storm slab avalanches will become likely today at all elevations.  CONSIDERABLE avalanche danger will exist today with avalanche danger expected to rise to HIGH tomorrow as this storm continues. 

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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Gale force SW winds will continue with increasing amounts of snowfall today and tonight.  Wind slab avalanches will be likely in near and above treeline areas where wind drifted snow has accumulated.  These wind slabs will be increasing in size throughout the day as additional snow becomes available for wind transport.  Natural wind slab avalanches will become possible today with human triggered avalanches likely.  These wind slab avalanches will become large enough to injure or bury a backcountry user.

Look for blowing snow, new cornice development, and developing wind pillows.  Make a plan to avoid steep wind loaded terrain and run out zones below large cornices.   

Avalanche Problem 2: Storm Slab
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Storm slabs will become likely as snowfall rates and amounts increase into the afternoon hours.  These storm slabs will develop in near and below treeline areas where previous snow cover has existed.  Storm slabs are expected to continue to be a problem overnight and into tomorrow as this storm brings additional snow.

Monitor new snow amounts while traveling in the backcountry.  Look for cracking or any signs of cohesion or slab formation within this new storm snow.  Utilize lower angle slopes and terrain features to limit your exposure to avalanche terrain. 

Forecast discussion

Our existing upper snowpack is made up of weak crusts and loose sugary faceted snow on northerly aspects in near and below treeline areas.  As this storm adds additional load to this weak snowpack structure, concern exists that these layers could fail and cause large deep slab avalanches.  With our current weather forecast, potential for these deep slab avalanches would begin overnight and into Sunday.  

recent observations
Submit Observations

Observations were received yesterday from Relay Peak and Incline Lake Peak (Mt. Rose area), Meiss Meadows (Carson Pass area), and Echo Lake (Echo Peak area).  Continued monitoring shows the upper snowpack on northerly terrain in near and below treeline areas to be made up of weak crusts and loose sugary snow.  The strength and distribution vary from location, but still remain a concern with a large loading event arriving.

 

Weather and CURRENT CONDITIONS
weather summary

A strong winter storm is starting to ramp up for our region with gale force SW winds and heavy snow expected.  2 to 4'' of new snow has fallen overnight with snowfall beginning to increase early this morning.  Forecasts call for 1 to 2 feet of snow at lake level with 2 to 4 feet along the Sierra Crest through Sunday.  Snowfall intensity is expected to increase late tonight and through the day on Sunday.  SW winds have been gusting over 100mph over the higher peaks and will remain gale force.  Snowfall could continue into the early part of next week.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 20 to 28 deg. F.
Max. temperature: 35 to 44 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 40 to 65 mph
Maximum ridgetop wind gust: 115 mph
New snowfall: 2 to 4 inches
Total snow depth: 36 to 49 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Saturday Saturday Night Sunday
Weather: Mostly cloudy. Snow likely in the morning, then snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 80%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 90%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 95%.
Temperatures: 33 to 39. deg. F. 21 to 26. deg. F. 28 to 33. deg. F.
Mid Slope Winds: Southwest 20 to 35 mph with gusts to 75 mph. Southwest 15 to 30 mph with gusts to 55 mph. Southwest 20 to 30 mph with gusts to 55 mph.
Expected snowfall: 70% probability of 3 to 6 inches. 30% probability of 6 to 10 inches. | SWE = 0.30-0.55 inch. 70% probability of 6 to 10 inches. 30% probability of 10 to 15 inches. | SWE = up to 0.85 inch. 70% probability of 7 to 12 inches. 30% probability of 12 to 16 inches. | SWE = 0.50-1.00 inch.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Mostly cloudy. Snow likely in the morning, then snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 80%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 90%. Cloudy. Snow. Snow levels below 7000 feet. Chance of precipitation is 90%.
Temperatures: 28 to 34. deg. F. 18 to 23. deg. F. 23 to 29. deg. F.
Ridge Top Winds: Southwest 35 to 55 mph with gusts to 90 mph. Southwest 30 to 50 mph with gusts to 80 mph. Southwest 30 to 45 mph with gusts to 75 mph.
Expected snowfall: 70% probability of 3 to 6 inches. 30% probability of 6 to 12 inches. | SWE = 0.35-0.55 inch. 80% probability of 7 to 12 inches. 20% probability of 12 to 18 inches. | SWE = 0.55-1.00 inch. 70% probability of 8 to 12 inches. 30% probability of 12 to 18 inches. | SWE = 0.55-1.05 inches.
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