Avalanche Advisory published on February 19, 2018 @ 6:58 am
This Avalanche Advisory expires in 16 hours, 51 minutes
This advisory is valid for 24 hours
Issued by Steve Reynaud - Tahoe National Forest

Considerable avalanche danger will exist today in near treeline and above treeline terrain due to wind slab avalanchesModerate avalanche danger will exist in all other areas.  Natural avalanches are possible with human triggered avalanches likely.  Dangerous avalanche conditions will exist today.

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Wind Slab
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    Certain
    Very Likely
    Likely
    Possible
    Unlikely
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    Very Large
    Large
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New wind slabs have formed overnight on NW-N-NE-E-SE aspects in near treeline and above treeline terrain.  In some areas, just under 1' of new snow fell overnight with strong to gale force SW winds.  Natural triggered avalanches will be possible and human triggered avalanches will be likely in wind loaded areas.  These avalanches could be large enough to injure or bury a backcountry user-size D2.  Winds are forecasted to shift to the NW today and be in the moderate to strong range with additional snow possible.  Wind slabs will continue to build through today and remain sensitive to triggering.

Look for blowing snow, cornice formation, and wind pillows.  Areas that received the most storm snow will have the largest wind slab potential.  Avoid steep wind loaded terrain and run out zones below wind loaded terrain. 

recent observations

* Observations from Chickadee Ridge (Mt. Rose backcountry) and Rubicon Peak (West Shore area) showed minor isolated, inconsequential wind slabs on some leeward slopes near ridgelines. Snow surfaces ranged from firm crusts in wind and/or sun exposed areas to soft snow in shaded wind protected areas. Snowpit data from these areas indicated a well-consolidated snowpack below the surface. This data is consistent with other observations across the forecast area in the last several days.

* Thin snow cover conditions exist throughout the forecast area on all aspects at lower elevations. Thin snow cover or bare ground exists on most sun-exposed aspects at all elevations with a few notable exceptions.

Weather and CURRENT CONDITIONS
weather summary

Cold low pressure will remain in our area for this week with below average temperatures and additional snow expected today and again on Thursday.  Yesterday into last night our area received 3 to 9'' of new snow throughout the forecast area with gale force SW winds.  Lake effect snow is possible in the Tahoe area for most of the day with 3 to 6'' of additional snow possible.  Very cold temperatures with below freezing wind chills are expected. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 2 to 5 deg. F.
Max. temperature in the last 24 hours: 24 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 30 to 45 mph
Maximum wind gust in the last 24 hours: 118 mph
New snowfall in the last 24 hours: 5 to 9 inches
Total snow depth: 30 to 55 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Today Tonight Tuesday
Weather: Mostly cloudy. Snow showers likely. Mostly cloudy then becoming partly cloudy. Snow showers throughout the night. Sunny
Temperatures: 16 to 21 deg. F. 3 to 8 deg. F. 20 to 26 deg. F.
Wind Direction: NW N
Wind Speed: 10 to 15mph with gusts to 35mph. 10 to 15mph in the evening becoming light. Gusts up to 30mph. Light winds
Expected snowfall: Likely 1 to 4 in | Possible 5 to 7 in. Up to 2 in. 0 in.
For 8000 ft. to 9000 ft.
Today Tonight Tuesday
Weather: Mostly cloudy. Snow showers likely. Mostly cloudy then becoming partly cloudy. Chance of snow showers through the night. Sunny
Temperatures: 10 to 16 deg. F. 1 below to 5 above zero deg. F. 15 to 21 deg. F.
Wind Direction: NW N N
Wind Speed: 15 to 25mph. Gusts to 45mph decreasing to 35mph in the afternoon. 10 to 15mph with gusts to 30mph. 10 to 15mph. Gusts up to 25mph in the morning.
Expected snowfall: Likely 1 to 4 in. | Possible 5 to 7 in. Up to 2 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

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