THIS AVALANCHE ADVISORY EXPIRED ON January 31, 2017 @ 6:59 am
Avalanche Advisory published on January 30, 2017 @ 6:59 am
Issued by Andy Anderson - Tahoe National Forest

LOW avalanche danger exists at all elevations, but some unstable snow may still linger on isolated terrain features. Evaluate the terrain and snowpack while traveling in the backcountry to identify where these isolated areas of unstable snow may still exist. Use normal caution when traveling in the backcountry.

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: Normal Caution
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

While triggering an avalanche remains unlikely, some unstable snow may still exist on isolated terrain features especially in steep complex or extreme terrain including couloirs, hanging snowfields, and steep cliffy areas. Large cornices still exist above many wind loaded slopes and the additional weight of a person on these cornices could still cause them to break. The warm sunny weather could make these cornices weaker and easier to trigger.

Assess the snowpack and terrain to identify where isolated areas of instability may linger. Practice safe backcountry travel techniques like using low angle slopes or ridgelines to approach terrain and only exposing one person at a time to avalanche terrain. Regroup in safe zones out of avalanche paths or runout zones. 

recent observations

Yesterday observations on Andesite Peak and in Negro Canyon found  a mix of snow surface conditions including soft unconsolidated snow on sheltered north aspects, wind scoured and wind packed surfaces on exposed near and above treeline slopes, wet snow and breakable sun crusts on sun-exposed E-SE-S-SW-W aspects above 7000 ft, and soft cold snow on all aspects below 7000 ft. where the air temps remained cold due to the inversion. In Negro Canyon, descending E facing test slopes triggered small roller balls and pinwheels and east facing cornices had water dripping off of them. Observations did not reveal any other signs of instability other than this wet surface snow. Surface hoar existed on open shaded slopes in both areas. 

Weather and CURRENT CONDITIONS
weather summary

The high-pressure ridge over the area will bring more sunny, calm, warm weather to the mountains today. Cold air that has pooled in the lower elevations should remain there due to the lack of wind. These inversion conditions should keep lower elevations much colder than the upper elevations. As of 6 am this morning, temperatures in the 8000-9000 ft. range had already risen into the upper 30's to low 40's while temperatures in the valleys remained in the 20's. The forecast calls for daytime highs in the upper 40's to low 50's above 7000 ft. today with mostly clear skies. By tonight the southwest winds should start to increase ahead of a storm approaching the region later this week. Some cloud cover may also start to build tonight and tomorrow. These winds and cloud cover should keep temperatures a few degrees cooler tomorrow.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 36 to 41 deg. F.
Max. temperature in the last 24 hours: 42 to 52 deg. F.
Average wind direction during the last 24 hours: Variable
Average wind speed during the last 24 hours: 10 mph
Maximum wind gust in the last 24 hours: 21 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 103 to 127 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Partly cloudy becoming sunny Clear becoming mostly cloudy Mostly cloudy
Temperatures: 44 to 50 deg. F. 19 to 29 deg. F. 43 to 48 deg. F.
Wind Direction: Variable Southwest Southwest
Wind Speed: Light 10 to 15 mph with gusts to 30 mph after midnight 15 to 20 mph with gusts to 35 mph increasing to 45 mph in the afternoon
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Partly cloudy becoming sunny Clear becoming mostly cloudy Mostly cloudy
Temperatures: 44 to 52 deg. F. 27 to 33 deg. F. 40 to 46 deg. F.
Wind Direction: Southwest Southwest Southwest
Wind Speed: Light with gusts to 25 mph in the morning 15 to 20 mph with gusts to 30 mph increasing to 45 mph after midnight 20 to 35 mph with gusts to 65 mph
Expected snowfall: 0 in. 0 in. 0 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