THIS AVALANCHE FORECAST EXPIRED ON November 23, 2020 @ 6:59 am
Avalanche Forecast published on November 22, 2020 @ 6:59 am
Issued by Brandon Schwartz - Tahoe National Forest

Stable snow is present in the vast majority of locations around the forecast area. The flip side is that very, very isolated areas of unstable snow may still exist. Use normal caution tactics to minimize the consequences of an unlikely and unexpected avalanche. Regional scale LOW avalanche danger exists at all elevations.

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Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Normal Caution
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Normal caution tactics are the name of the game today. The vast majority of locations out there today will look stable and act stable. The concern is for the potential outlier of a very, very isolated NW-N-NE aspect below treeline or near treeline that still holds some lingering instability. The weak layer would be the remnants of the Nov 13 facet layer located a few inches above ground level.

An avalanche today would come as a surprise for those involved. Use the normal caution tactics of making a plan, carrying companion rescue gear, using effective communication to ensure that all party members understand the plan and the hazard. Expose only one person at a time to avalanche terrain, do not rely on marginal safe zones, and do not underestimate the avalanche size potential on a small slope. These are the tactics to minimize the consequences of an unexpected avalanche.

Increasing SW winds today are not expected to cause much in the way of blowing and drifting snow that would deposit in lee areas as problematic new wind slab development. If you do encounter areas of visibly drifting snow, take a minute to pause and evaluate. Ridgeline locations near existing cornice overhangs hold the greatest potential for drifting snow. Slopes below cornices are easy to avoid with only minor route changes.

 

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The snowpack tends to be supportable but remains thin with numerous obstacles to hit. The best coverage exists above 7,300' to 7,800’ along the Sierra Crest and above 8,600’ in the Mt. Rose area.

We have been tracking strength gains on the previously problematic Nov 13 weak layer of facets near the bottom of the snowpack. Stabilization does not occur at the same rate in all locations. However, in the vast majority of locations around the forecast area, snowpit data has indicated that this layer has bonded well to the snow above and below it in recent days with no further indications of instability. The only known outlier are unstable snowpit tests on this weak layer that occurred Friday above "The Grills" just west of Mt. Lola (Independence Lake area) in northerly aspect below treeline to near treeline terrain around +/-8,000'. Snowpit data collected yesterday about 5 miles to the east of this area on a below treeline NE aspect at about 8,400' gave no indications of instability on the Nov 13 facet layer. Any lingering instability is very isolated. No avalanches have been reported failing on this layer since the peak of instability back on Wednesday (Nov 18).

Weather and CURRENT CONDITIONS
weather summary

A weak weather system will pass mainly to the north of the forecast area today and tomorrow. Dry conditions are expected to continue for our area. The noticeable impacts will be a few degrees of warming today, periods of mid to high level cloud cover, and moderate speed SW ridgetop winds. For tomorrow a few degrees of cooling are expected. Ridgetop winds are forecast to shift to more W to NW, remaining moderate speed. A brief break with sunny skies and light winds is forecast for Tuesday. There is currently a low chance for precipitation to return to the forecast area Wednesday/Thursday.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 33 to 36 deg. F.
Max. temperature: 39 to 47 deg. F.
Average ridgetop wind direction: NE shifting to SW
Average ridgetop wind speed: 15 mph
Maximum ridgetop wind gust: 27 mph
New snowfall: 0 inches
Total snow depth: 15 to 22 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Sunday Sunday Night Monday
Weather: Partly cloudy then becoming sunny. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 0%. Mostly cloudy then becoming partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy then becoming sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 42 to 47. deg. F. 24 to 32. deg. F. 36 to 41. deg. F.
Mid Slope Winds: Light winds becoming southwest around 15 mph in the afternoon with gusts up to 25 mph. Southwest around 15 mph with gusts to 25 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.
Sunday Sunday Night Monday
Weather: Partly cloudy then becoming sunny. Snow levels 7000 feet. Chance of precipitation is 0%. Mostly cloudy then becoming partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy then becoming sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 37 to 42. deg. F. 23 to 29. deg. F. 32 to 38. deg. F.
Ridge Top Winds: Southwest 15 to 20 mph with gusts to 35 mph. Southwest 15 to 20 mph with gusts to 35 mph. West 15 to 20 mph with gusts to 35 mph.
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