THIS AVALANCHE ADVISORY EXPIRED ON March 5, 2017 @ 6:59 am
Avalanche Advisory published on March 4, 2017 @ 6:59 am
Issued by Andy Anderson - Tahoe National Forest

LOW avalanche danger exists for all elevations until new snow starts to accumulate this afternoon/evening. Some areas of instability can still exist on isolated terrain features during LOW danger.

Once it begins snowing, the avalanche danger will increase rapidly as WIND SLABS and STORM SLABS form. During the night natural avalanches will become possible and the avalanche danger will rise to CONSIDERABLE. Expect dangerous avalanche conditions in the backcountry tonight and tomorrow. Check back tomorrow morning for the latest updates. 

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 avalanche activity will remain unlikely during the day today, some unstable snow may still linger on isolated terrain features especially in complex or extreme terrain like couliors, steep convex rollovers, or unsupported snow slopes.

As new snow starts to fall this afternoon, WIND SLABS and STORM SLABS will start to build on top of the snowpack. These will increase in size quickly during the night due to intense snowfall rates and strong winds. They will form faster than they can bond to the old snow. Some weaknesses will likely form within the storm snow as well. Human triggered wind slab and storm slab avalanches will become likely tonight and some natural avalanches will be possible. If the storm arrives sooner than expected, these avalanche problems will also form sooner. If for some reason backcountry travel is required tonight, dangerous avalanche conditions will exist. Expect dangerous avalanche conditions in the backcountry tomorrow as well as the storm continues.

recent observations

Yesterday observations on Castle Peak and on Rubicon Peak found soft unconsolidated snow remaining on the N aspects above 8000 ft, and a mix of frozen crusts and wet sticky snow below 8000 ft. on northerly aspects and on all other aspects up to above 9000 ft. Snowpit data and general observations did not reveal signs of lingering slab instabilities and indicated that the snowpack should be ready to handle new snow loading

Weather and CURRENT CONDITIONS
weather summary

The southwest winds and cloud cover have steadily increased since yesterday. They should continue to increase through today as a winter storm pushes into the region. The southwest winds will remain strong through the storm. Snowfall could start this afternoon and should continue through tomorrow. This storm will bring colder temperatures with it, and snow levels should start around 5500 ft. and fall to 3000 ft. or below by tomorrow. Snowfall should intensify this evening and remain heavy through tomorrow morning. The forecast calls for snow to continue all day tomorrow. The forecast calls for 1 to 2 feet of new snow above 7000 ft. and 10 to 18 inches above 5500 ft. by tomorrow afternoon. For more information check in with the Reno NWS

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 26 to 33 deg. F.
Max. temperature in the last 24 hours: 37 to 50 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 25 to 35 mph
Maximum wind gust in the last 24 hours: 71 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 130 to 179 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 with snow likely in the afternoon Snow Snow
Temperatures: 37 to 42 deg. F. 21 to 26 deg. F. 23 to 28 deg. F.
Wind Direction: Southwest Southwest Southwest
Wind Speed: 20 to 35 mph with gusts to 50 mph increasing to 60 mph in the afternoon 25 to 35 mph with gusts to 65 mph 20 to 35 mph with gusts to 50 mph
Expected snowfall: up to 1 in. 6 to 12 in. 7 to 14 in.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Mostly cloudy with snow likely in the afternoon Snow Snow
Temperatures: 29 to 37 deg. F. 15 to 21 deg. F. 15 to 21 deg. F.
Wind Direction: Southwest Southwest Southwest
Wind Speed: 30 to 50 mph with gusts to 95 mph 40 to 60 mph with gusts to 115 mph 30 to 50 mph with gusts to 115 mph decreasing to 25 to 35 mph with gusts to 80 mph in the afternoon
Expected snowfall: up to 1 in. 6 to 12 in. 7 to 14 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