THIS AVALANCHE ADVISORY EXPIRED ON February 22, 2018 @ 6:50 am
Avalanche Advisory published on February 21, 2018 @ 6:50 am
Issued by Steve Reynaud - Tahoe National Forest

Low avalanche danger will exist throughout the forecast area at all elevations today.  Watch for wind slabs in isolated near and above treeline terrain.  Avalanche danger is expected to rise tomorrow as an approaching storm brings light to moderate snowfall with increasing winds. 

 

1. Low

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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: Wind Slab
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  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
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    Very Large
    Large
    Small

For today, wind slabs may exist in isolated near and above treeline areas.  As our next storm approaches tonight, increasing SW winds with additional snowfall will start to build new winds slabs.  These wind slabs will be on NW-N-NE-E-SE aspects in near and above treeline terrain.  Limited new snowfall and winds are expected until Thursday morning.  Any new wind slab development overnight should be small until the morning when avalanche danger is expected to rise.

Look for blowing snow, cornice formation, and wind pillows as to clues to where wind slabs exist.  Avoid steep wind loaded terrain.

recent observations

* Observations from Grouse Rock (Ward Canyon area) and Black Butte (Carson Pass area) continued to show minimal wind slab development.  2 to 6'' of storm snow was seen in both areas.  Variable winds existed with differing amounts of snow transport observed.

* Wind scoured firm crusts exist in many exposed near and above treeline terrain.

* Thin snow cover conditions exist throughout the forecast area on all aspects at lower elevations. Thin snow cover or bare ground exists on most sun-exposed aspects at all elevations.

Weather and CURRENT CONDITIONS
weather summary

Light to moderate snowfall is expected late tonight through Thursday as another cold low pressure system moves into our area.  With cold air in place, high snow ratios are expected with low visibility due to blowing snow.  We dry out for the weekend with another, potentially larger storm, forecasted for Monday/Tuesday.  This cold pattern sticks with us into at least the first week of March with the possibility of larger storms to come.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 3 to 11 deg. F.
Max. temperature in the last 24 hours: 20 to 23 deg. F.
Average wind direction during the last 24 hours: Variable
Average wind speed during the last 24 hours: 5 to 20 mph
Maximum wind gust in the last 24 hours: 47 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 31 to 52 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 then becoming partly cloudy. Scattered snow showers. Mostly cloudy then becoming partly cloudy. Scattered snow showers. Cloudy. Widespread snow showers.
Temperatures: 20 to 29 deg. F. 11 to 16 deg. F. 19 to 25 deg. F.
Wind Direction: SW SW
Wind Speed: Light winds Light winds becoming SW at 10 to 15mph with gusts to 45mph after midnight. 15 to 20mph. Gusts to 60mph decreasing to 35mph in the afternoon.
Expected snowfall: Up to 1 in. Likely up to 1 in. | Possible 2 to 3 in. Likely 2 to 6 in. | Possible 7 to 10 in.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy then becoming partly cloudy. Scattered snow showers. Mostly cloudy then becoming partly cloudy. Scattered snow showers. Cloudy. Widespread snow showers.
Temperatures: 10 to 20 deg. F. 5 to 13 deg. F. 8 to 15 deg. F.
Wind Direction: SW SW
Wind Speed: Light winds Light winds becoming SW 15 to 25mph with gusts to 60mph after midnight. SW 25 to 40mph with gusts to 80mph becoming W 15 to 20mph with gusts to 45mph in the afternoon.
Expected snowfall: Up to 1 in. Likely up to 1 in. | Possible 2 to 4 in. Likely 3 to 7 in. | Possible 8 to 12 in.
Disclaimer

This avalanche advisory is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This advisory 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 advisory applies only to backcountry areas outside established ski area boundaries. This advisory describes general avalanche conditions and local variations always occur. This advisory expires 24 hours after the posted time unless otherwise noted. The information in this advisory is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258