THIS AVALANCHE ADVISORY EXPIRED ON December 8, 2015 @ 6:41 am
Avalanche Advisory published on December 7, 2015 @ 6:41 am
Issued by Brandon Schwartz - Tahoe National Forest

LOW avalanche danger continues for all elevations and aspects. Small isolated pockets of unstable snow may exist. Normal caution is advised. It is still early season with generally shallow snow coverage and numerous poorly covered obstacles to hit.

1. Low

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Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Normal Caution
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  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Avalanche concerns for today are few. Strong SW winds yesterday created very small newly formed wind slabs near and above treeline in lee areas. The largest slabs were noted in the Mount Rose area. Overall, the size of these wind slabs is not expected to present a significant hazard to backcountry travelers unless located above cliffs or other secondary terrain hazards that greatly increase consequences. Some minor human triggered cracking might be observed today on these very small wind slabs.

With continued warming across all elevations, some minor roller ball activity might occur today mainly in areas that received new snow yesterday. Problematic loose wet avalanche activity is not expected.

recent observations

Observations made yesterday on Lincoln Ridge (Yuba Pass area), Castle Peak (Donner Summit area), Tamarack Peak (Mount Rose area), and in the Meiss Drainage (Carson Pass area) revealed a wide mix of conditions. On Lincoln Ridge, light snowfall changing to rain on snow was observed up to the ridge high point around 7,700'. Hand pits in the area revealed no issues with basal facets. On Castle Peak around one inch of new snow was observed with no signs of rain at elevations similar to Lincoln Ridge. Small amounts of new wind loading were noted in lee areas near and above treeline. Snowpit tests targeting basal facets indicated ongoing rounding of these snow crystals and still potentially problematic but very difficult to trigger snowpack failures. On Tamarack Peak around 2 inches of new snow was observed with the formation of very small new wind slabs in lee areas. Snowpit test targeting basal facets revealed loose grains and potentially problematic but very difficult to trigger snowpack failures. In the Meiss Headwaters less cloud cover along with warm and windy conditions were observed. By mid afternoon 2 to 4 inches of wet surface snow existed on sun exposed slopes. Significant amounts of previous wind scouring were observed with small wind slabs showing minor skier triggered cracking in lee areas. Loose grained basal facets were easy to find in shaded areas both near treeline and above treeline.

Weather and CURRENT CONDITIONS
weather summary

Weak high pressure over the region will push storms just to the north of the forecast area for the next few days. Mid to high level cloud cover mixed with periods of sun are expected today and tomorrow. With continued westerly flow aloft, nightly air temperature inversions will be kept from forming in the mountain valleys. A continuation of the warming trend is expected with maximum daytime air temperatures above 7,000' in the low to upper 40s today and mid 40s to mid 50s for tomorrow. Confidence continues to increase in a powerful storm system impacting the forecast area later this week.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 31 to 38 deg. F.
Max. temperature in the last 24 hours: 33 to 41 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 37 mph
Maximum wind gust in the last 24 hours: 83 mph
New snowfall in the last 24 hours: 0 to 2 inches
Total snow depth: 15 to 22 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Monday Monday Night Tuesday
Weather: Mostly cloudy skies. Mostly cloudy skies. Mostly cloudy skies.
Temperatures: 43 to 50 deg. F. 28 to 36 deg. F. 47 to 54 deg. F.
Wind Direction: SW SW SW
Wind Speed: 20 to 30 mph with gusts to 45 mph. 15 to 25 mph with gusts to 40 mph. 15 to 20 mph with gusts to 30 mph.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Monday Monday Night Tuesday
Weather: Mostly cloudy skies. Mostly cloudy skies. Mostly cloudy skies.
Temperatures: 41 to 48 deg. F. 28 to 35 deg. F. 44 to 51 deg. F.
Wind Direction: SW W W
Wind Speed: 30 to 40 mph with gusts to 60 mph. 30 to 40 mph with gusts to 60 mph. Gusts decreasing to 50 mph after midnight. 20 to 30 mph with gusts to 45 mph.
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.