THIS AVALANCHE ADVISORY EXPIRED ON March 26, 2016 @ 6:51 am
Avalanche Advisory published on March 25, 2016 @ 6:51 am
Issued by Andy Anderson - Tahoe National Forest

LOW avalanche danger exists this morning, but MODERATE avalanche danger will form on sun-exposed E-SE-S-SW-W aspects steeper than 35 degrees at all elevations as last night's refreeze melts. Loose wet avalanches will become possible due to daytime warming today. Enough warming may also occur on the low elevation NW-N-NE aspects for some loose wet activity as well. Some loose wet snow avalanches could entrain enough snow to pose a threat to backcountry travelers especially in areas where terrain traps exist.

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

Increased winds should slow some of the melting that occurs today, but they will not cause enough cooling to prevent the strong March sunshine and warm daytime temperatures from forming a deep layer of wet snow on sun-exposed slopes today. Loose wet avalanches involving this wet snow will become possible once last night's refreeze melts. Most of the loose wet instabilities that do occur should consist of small roller balls, pinwheels, and point releases, but some larger loose wet avalanches that entrain enough snow to cause problems for backcountry travelers could still occur. Slopes steeper than 35 degrees on sun-exposed E-SE-S-SW-W aspects at all elevations will hold the best potential for loose wet activity since they should experience the most warming, but some of the lower elevation NW-N-NE aspects could also see enough sun for some wet snow issues to form.

Sinking into wet snow above your boot tops and small surface instabilities like roller balls, pinwheels, or point releases can provide clues that enough wet snow has formed for loose wet avalanches to become an issue. Once deep wet snow exists on a slope, changing aspects to find more frozen slopes or moving onto lower angle slopes off and away from slopes 35 degrees or steeper represent wise choices. Terrain traps like gullies, creeks, and cliffs can greatly increase the risk of any size loose wet avalanches.

recent observations

Yesterday human triggered roller balls, point releases, and pinwheels up to 4 ft. in diameter started to occur on E-SE-S facing slopes below 8000 ft. on Caslte Peak (Donner Summit area) by 11 am and on low elevation road cuts between Truckee and Carson Pass by 9 am. Deep wet snow and smaller loose wet instabilities also existed on many of the upper elevation sun-exposed E-SE-S-SW slopes by noon on Castle Peak and on Meiss Ridge (north of Carson Pass).  Some of the more exposed and previously wind scoured or wind packed slopes on these aspects held less deep, wet, almost corn snow on top of mostly supportable melt freeze crusts. Observations on the north aspects in both of these areas showed wind scoured surfaces near the ridgelines and cold soft snow below the ridgelines at the upper elevations. Below about 8600 ft. in the Miess area, the snow on the north aspects became wet and sticky.

Weather and CURRENT CONDITIONS
weather summary

A system moving through eastern NV should cause the winds to shift to the northwest and northeast and increase this afternoon and tonight, but skies should remain mostly sunny and temperatures should still climb into the mid to upper 40's and maybe the low 50's above 7000 ft. today. The winds should decrease some tomorrow afternoon and the forecast calls for sunny skies with warm temperatures a degree or two cooler than today. 

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 30 to 38 deg. F.
Max. temperature in the last 24 hours: 41 to 48 deg. F.
Average wind direction during the last 24 hours: Southwest to northwest
Average wind speed during the last 24 hours: 10 to 15 mph
Maximum wind gust in the last 24 hours: 33 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 79 to 119 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy becoming sunny Clear Sunny
Temperatures: 43 to 50 deg. F. 22 to 29 deg. F. 42 to 49 deg. F.
Wind Direction: West Northeast East
Wind Speed: 10 to 15 mph with gusts to 25 mph 10 to 15 mph with gusts to 30 mph 10 to 15 mph with gusts to 25 mph decreasing in the afternoon
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy becoming sunny Clear Sunny
Temperatures: 36 to 44 deg. F. 22 to 29 deg. F. 36 to 44 deg. F.
Wind Direction: Northwest North shifting to the northeast after midnight Northeast shifting southeast in the afternoon
Wind Speed: 20 to 30 mph with gusts to 45 mph 30 to 35 mph with gusts to 50 mph decreasing to 20 to 25 mph with gusts to 35 mph after midnight 25 to 30 mph with gusts to 45 mph decreasing to 10 to 15 mph with gusts to 25 mph in the afternoon
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.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258