THIS AVALANCHE ADVISORY EXPIRED ON February 11, 2016 @ 6:44 am
Avalanche Advisory published on February 10, 2016 @ 6:44 am
Issued by Steve Reynaud - Tahoe National Forest

Low avalanche danger will exist on all aspects and elevations in the early morning hours.  As daytime warming begins, pockets of Moderate avalanche danger will become possible on E-SE-S-SW aspects at all elevations due to loose wet avalanche instabilities.  On W-NW-N-NE aspects at all elevations, avalanche danger will remain Low throughout the day.

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
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Air temperatures above 7000' were well above freezing for another night with temps at 6am in the mid 30's to mid 40's.  Southwest winds will be in the light to moderate range above 7000' for today.  Under mostly clear skies last night, radiational cooling should have helped to marginally refreeze the snow surface.  Any refreeze is expected to be thin in most areas and melt quickly this morning.

Human triggered loose wet avalanche activity will become possible on E-SE-S-SW aspects on slopes above 35 degrees as daytime warming occurs and the upper snowpack looses supportability.  Most of these loose wet avalanches will be in the form of human triggered pin wheels or roller balls.  In some cases, these loose wet avalanches could be large enough to injure or bury a backcountry user. 

Timing will be important if you plan to travel on solar aspects today.  Avoid steep solar aspects and terrain traps as daytime warming occurs.  Current roller balls or pin wheels will be an indication that the snow surface has lost supportability and strength.  Hand pits and boot penetration may help give clues to upper snowpack strength.  

recent observations

Observations from Caples Lake (Carson Pass area), Castle Peak (Donner Summit Area), and Incline Lake Peak (Mt. Rose area) all showed warm, spring like conditions.  Good snow travel was reported in the mid morning hours with conditions deteriorating quickly by noon.  On Incline Lake Peak, skier triggered loose wet avalanches were reported in the small size.  On Castle Peak, firm snow surfaces exist in exposed areas that were scoured by the recent East wind event.  North aspects on Incline Lake Peak, had pockets of unconsolidated snow mixed with variable and sticky snow at all elevations.  All locations reported punchy and unsupportable surface snow conditions on solar aspects by mid day.

Weather and CURRENT CONDITIONS
weather summary

High pressure continues with warm temperatures and light winds with a gradual warming trend into Friday.  Mid to high level clouds will stream across the Sierra today from a trough that is towards our north.  Valley inversions are still in place but should diminish over the next few days as increased southwest flow allows for better mixing.  Temperatures above 7000' at 6am this morning range from the mid 30's to mid 40's.  Highs for the day above 8000' are expected in the mid 40's to mid 50's.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 23 to 43 deg. F.
Max. temperature in the last 24 hours: 39 to 50 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: 38 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 64 to 81 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Partly cloudy. Partly cloudy. Partly cloudy.
Temperatures: 47 to 54 deg. F. 27 to 35 deg. F. 47 to 54 deg. F.
Wind Direction: SW W SE
Wind Speed: 10 to 15mph with gusts to 25mph. 10 to 15mph shifting to the SE after midnight. 10 to 15mph in the morning becoming light.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Partly cloudy. Partly cloudy. Partly cloudy.
Temperatures: 44 to 51 deg. F. 25 to 32 deg. F. 45 to 52 deg. F.
Wind Direction: SW S S
Wind Speed: 15 to 25mph with gusts to 35mph. 15 to 25mph with gusts to 35mph. 15 to 20mph with gusts to 30mph.
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.