THIS AVALANCHE ADVISORY EXPIRED ON February 17, 2014 @ 7:00 am
Avalanche Advisory published on February 16, 2014 @ 7:00 am
Issued by Andy Anderson - Tahoe National Forest

Near and above treeline pockets of MODERATE avalanche danger may exist on slopes 35 degrees and steeper on NW-N-NE-E-SE aspects due to newly formed wind slabs. In wind protected areas below treeline and in wind scoured areas near and above treeline, avalanche danger remains LOW.

2. Moderate

?

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

2. Moderate

?

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

1. Low

?

Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Strong southwest winds and 3-6 inches of new snow last night with up to 3 more inches of snow possible this morning means that some wind slabs will have formed on the leeward NW-N-NE-E-SE aspects. Most of these wind slabs should remain relatively small due to the small amounts of new snow that fell. In heavily wind loaded areas that received the most snow the wind slabs could reach 1-2 ft in depth. These pockets of larger wind slabs will likely exist on some of the near and above treeline wind-loaded N-NE-E aspects and the cross-loaded NW and SE aspects. Human triggering of these new wind slabs will be possible today. 

recent observations

Yesterday observations near Lincoln Ridge on Yuba Pass and on Becker Peak near Echo Summit showed a snowpack that consisted of wet melt-freeze snow and old crusts with thick rain crusts on top of everything up to at least 8000 ft. Observations from 2/14 indicated that the rain crust likely exists as high as 9800 ft. Yesterday the thick crust on the surface had refrozen enough on Becker Peak to sometimes support a skier and sometimes it would break under the weight of a skier. A person on foot would consistently break through the crust and sink deep into wet snow. On Yuba Pass the rain crust would support snowmobiles and in some places it would support a person on foot. In other places a person on foot would sink deep into wet snow. In both of these areas snowpit tests and general observations indicated that the snowpack continues to consolidate and refreeze, and did not reveal any signs of instability. 

Weather and CURRENT CONDITIONS
weather summary

The southwest winds increased yesterday ahead of a small storm that has deposited 3 to 6 inches of new snow above 7000 ft. As this storm departs, snow showers should taper off this morning and skies should begin to clear as a small ridge of high pressure fills in behind the storm. The forecast calls for the strong winds to start decreasing this afternoon and tonight. By tomorrow the southwest winds should begin to increase again. The forecast calls for daytime highs above 7000 ft. in the 30's today and upper 30's to low 40's tomorrow. Overnight lows should fall into the 20's.  

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 24 to 29 deg. F.
Max. temperature in the last 24 hours: 36 to 44 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 30 to 45 mph
Maximum wind gust in the last 24 hours: 80 mph
New snowfall in the last 24 hours: 3 to 6 inches
Total snow depth: 40 to 51 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Sunday Sunday Night Monday
Weather: Snow showers ending this morning. Skies becoming partly cloudy to mostly sunny by this afternoon Clear Partly cloudy to mostly sunny
Temperatures: 35 to 42 deg. F. 24 to 29 deg. F. 38 to 45 deg. F.
Wind Direction: Southwest shifting to the west in the afternoon Southwest Southwest
Wind Speed: 20 to 35 mph with gusts to 50 mph decreasing to 10 to 20 mph with gusts to 30 mph in the afternoon 10 to 20 mph with gusts to 30 mph 15 to 25 mph with gusts to 40 mph
Expected snowfall: 0 to 2 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Sunday Sunday Night Monday
Weather: Snow showers ending this morning. Skies becoming partly cloudy to mostly sunny by this afternoon Clear Partly cloudy to mostly sunny
Temperatures: 30 to 35 deg. F. 23 to 29 deg. F. 34 to 40 deg. F.
Wind Direction: Southwest shifting to the west in the afternoon Southwest Southwest
Wind Speed: 30 to 45 mph with gusts to 60 mph decreasing to 20 to 35 mph with gusts to 50 mph in the afternoon 15 to 25 mph with gusts to 40 mph 30 to 40 mph with gusts to 60 mph
Expected snowfall: up to 3 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.