THIS AVALANCHE ADVISORY EXPIRED ON February 25, 2016 @ 6:48 am
Avalanche Advisory published on February 24, 2016 @ 6:48 am
Issued by Steve Reynaud - Tahoe National Forest

Avalanche danger is low for all aspects and elevations through the early morning hours.  As daytime warming occurs, avalanche danger will rise to Moderate on E-SE-S-SW-W aspects on slopes steeper than 35 degrees due to the possibility of loose wet avalanches.  Isolated loose wet instability may occur on some NW-N-NE aspects as well.

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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    Certain
    Very Likely
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    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
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Snow surface conditions on solar aspects are going through a slow transition from recent storm snow towards an established melt freeze crust.  In many areas, the upper snowpack structure has several inches of wet surface snow on top of colder, more winter like snow below.  Overnight lows were above freezing at most locations above 8000'.  Temperatures are forecasted to increase today with lighter winds out of the SW.  Most of the loose wet avalanches expected today will be in the form of roller balls or pinwheels.  Although, larger loose wet avalanches are possible with enough snow to injure or bury a backcountry user.  The vast majority of instability is expected to occur on E-SE-S-SW-W aspects on slopes steeper than 35 degrees. Isolated instability may also occur on low to mid elevation NW-N-NE aspects

Avoid solar aspects steeper than 35 degrees once the snow surface has more than a few inches of wet snow on top of the transitional recent storm snow.  Hand pits can be a quick and valuable tool to use to determine the structure of the upper snowpack.  Current roller balls and pinwheels indicate that the snow surface is loosing strength and that loose wet avalanches are possible.

recent observations

Observations throughout the forecast area over the last few days show a transitioning snowpack.  On shaded northerly aspects, areas of unconsolidated snow exist with other areas of crusts, sticky snow, and wind scoured surface snow.  On solar aspects, the recent storm snow is transitioning towards a melt freeze crust.  In most areas, there are several inches of wet snow on top of colder dryer snow below.  The recent N-NE winds have helped to keep conditions cooler at the upper elevations and limit most loose wet instabilities.  No evidence of any significant wind transport has been observed with these N-NE winds.

On Lincoln Ridge (Yuba Pass area) surface snow was wet on southerly aspects but was mostly ski supportive at mid day.  Shaded northerly aspects was a mix of crusts, unconsolidated snow, and sticky heavy snow. 

Weather and CURRENT CONDITIONS
weather summary

High pressure is firmly in place with well above average temperatures expected for the next couple days.  Valley inversions are trapping cooler air down low with warmer air at the higher elevations.  Overnight lows above 8000' were in the mid 30's to low 40's.  Forecasted highs are expected to be in the mid 40's to low 50's above 8000' today with light to moderate SW winds.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 33 to 39 deg. F.
Max. temperature in the last 24 hours: 49 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 15 to 20 mph
Maximum wind gust in the last 24 hours: 27 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 56 to 89 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny Partly cloudy. Sunny then becoming partly cloudy.
Temperatures: 50 to 56 deg. F. 29 to 36 deg. F. 52 to 58 deg. F.
Wind Direction: SW SW
Wind Speed: 5 to 15mph in the morning becoming light. Light winds Up to 10mph.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny Partly cloudy Sunny then becoming partly cloudy.
Temperatures: 43 to 51 deg. F. 34 to 40 deg. F. 45 to 52 deg. F.
Wind Direction: SW SW SW
Wind Speed: 15 to 25mph with gusts to 35mph. 10 to 15mph with gusts to 25mph. 10 to 15mph with gusts to 25mph.
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.