THIS AVALANCHE ADVISORY EXPIRED ON February 13, 2018 @ 6:55 am
Avalanche Advisory published on February 12, 2018 @ 6:55 am
Issued by Andy Anderson - Tahoe National Forest

The avalanche danger should remain LOW today. Despite the LOW danger rating, some very small, shallow wind slabs may lurk on isolated terrain features in near and above treeline terrain.

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

Avalanche activity large enough to bury a person should remain unlikely today due to the minimal amounts of current and forecasted new snow accumulation. However, some small wind slabs may exist near ridgelines on isolated terrain features where the most new snow accumulates and where the most wind-loading occurs. These wind slabs could exist on any aspect due to the shifting winds, but they should remain very shallow and should not extend more than a few feet from the ridgelines. 

Other dangers like falls on frozen crusts, collisions with some of the numerous exposed obstacles, or both still exist. Continue to plan travel in the backcountry to minimize risks. 

recent observations

* Snow surfaces remained frozen on any slopes where snow had been through melt-freeze cycles during the warm weather including E-SE-S-SW-W aspects in the Carson Pass, Donner Summit and Mt. Rose areas.

* Snow coverage on E-SE-S-SW-W aspects varies significantly by location and elevation. In some areas, little to no continuous snow cover exists on these aspects below 8,200' to 9,000'. In some cases, these aspects are mostly bare ground up to elevations above 10,000'.

* Snowpit data and observations from N aspects on Elephant's Hump (Carson Pass area) in an area where previous tests yielded unstable results did not reveal any signs of instability. 

* Observers reported some areas of minor blowing snow near ridgelines yesterday on Elephant's Hump and on Incline Lake Peak (Mt. Rose backcountry).

* Some soft, cold, unconsolidated surface snow still lingers on sheltered untracked N aspects across the forecast area. Snow surface conditions elsewhere on NW-N-NE aspects range from breakable crust to heavily tracked to firm wind scoured. Snow coverage becomes less consistent and more limited on northerly aspects below 7500 ft. in most areas.

Weather and CURRENT CONDITIONS
weather summary

Yesterday's strong gusty winds decreased overnight as light snow and cold temperatures moved into the forecast area. Most remote sensors across the forecast area indicate 1 to 2 inches of snow fell overnight. One sensor reported 3 inches. Another wave of snow showers continues to work its way south through the region and the forecast calls for up to 2 more inches of snow especially in areas south of Lake Tahoe. Snow showers should end tonight with partly cloudy to sunny skies forecast for tomorrow. The winds have started to shift to the E and NE. These E and NE winds should increase this afternoon and through the night before decreasing tomorrow.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 17 to 21 deg. F.
Max. temperature in the last 24 hours: 35 to 39 deg. F.
Average wind direction during the last 24 hours: SW shifting to the east this morning
Average wind speed during the last 24 hours: Yesterday: 45 mph | Last night: 15 mph
Maximum wind gust in the last 24 hours: 100 mph
New snowfall in the last 24 hours: 1 to 2 inches
Total snow depth: 27 to 48 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Mostly cloudy with a chance of snow in the morning then widespread snow showers in the afternoon Mostly cloudy with some scattered snow showers becoming partly cloudy Partly cloudy becoming sunny
Temperatures: 25 to 30 deg. F. 14 to 19 deg. F. 31 to 36 deg. F.
Wind Direction: Northeast Northeast Northeast
Wind Speed: Light in the morning increasing to 10 to 15 mph in the afternoon 10 to 15 mph with gusts to 25 mph 10 to 15 mph with gusts to 30 mph in the morning becoming light in the afternoon
Expected snowfall: up to 1 in. up to 1 in. 0 in.
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Mostly cloudy with a chance of snow in the morning then widespread snow showers in the afternoon Mostly cloudy with some scattered snow showers becoming partly cloudy Partly cloudy becoming sunny
Temperatures: 18 to 26 deg. F. 11 to 17 deg. F. 25 to 31 deg. F.
Wind Direction: Northwest shifting to the northeast in the afternoon Northeast East
Wind Speed: 10 to 15 mph with gusts to 25 mph 15 to 25 mph with gusts to 35 mph 20 to 30 mph with gusts to 60 mph decreasing to 10 to 15 mph with gusts to 40 mph in the afternoon
Expected snowfall: up to 2 in. up to 1 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