THIS AVALANCHE FORECAST EXPIRED ON February 25, 2018 @ 6:52 am
Avalanche Forecast published on February 24, 2018 @ 6:52 am
Issued by Brandon Schwartz - Tahoe National Forest

MODERATE avalanche danger lingers near and above treeline. LOW avalanche danger exists below treeline. Blowing snow is expected today with the possibility of a wind slab avalanche problem. Air temperatures warming to near freezing today will allow for a very slight possibility of a loose wet avalanche problem.

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.

1. Low

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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
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Increasing SW to W winds today will create areas of blowing snow in near treeline and above treeline terrain. Redistribution of snow on the ground will allow for the possibility of new wind slab formation. New wind slabs may be difficult to trigger today (stubborn or possibly unreactive).  New wind slabs will likely be small with a potential avalanche size of D1 expected (not large enough to bury a person). Consequences would come from being pushed into rocks or trees, over a cliff, or into a terrain trap.

Identify and avoid areas of potentially unstable wind slab by looking for newly wind drifted snow. Slopes that have cornice features or wind pillows across the upper portion of the slope are the most suspect. Areas of snow surface cracking in near treeline and above treeline terrain are an additional indication of unstable snow.

Avalanche Problem 2: Loose Wet
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Loose wet is an unlikely avalanche problem today but cannot be ruled out if strong solar radiation occurs simultaneously with near freezing air temperatures during the mid day or afternoon hours. This will be fairly dependent on how rapidly and to what extent sun obscuring cloud cover develops today.

Look for natural or human triggered roller balls occurring in sun exposed, wind protected areas near treeline and below treeline on SE-S-SW aspects as the first sign of the potential for small (size D1) loose wet avalanches to occur.

recent observations
Submit Observations

* Blowing snow with little in the way of problematic wind slab formation has been noted near and above treeline around the forecast area over the past two days. Winds have shifted back and forth between SW and NE.

* A few very small loose dry avalanches were observed yesterday on very steep slopes in the Ebbetts Pass area.

* Faceted snow either with or without an associated crust has been noted 1 to 1.5 feet below the snow surface in the Carson Pass and Ebbetts Pass areas. This layer warrants monitoring but has yet to become problematic due to the low density and lack of slab characteristics in the overlying snow.

Weather and CURRENT CONDITIONS
weather summary

A weather system will pass by to the NE of the forecast area today. The main impacts will be increasing winds and cloud cover this afternoon with the slight possibility of a few light snow showers over the forecast area. Ridgetop winds are expected to become strong out of the SW this afternoon. Upper elevation winds are forecast to shift to the N tonight and then back to the SW tomorrow. A gradual warming of maximum daytime air temperatures will continue today and tomorrow. The next possibility of meaningful snowfall across the forecast area occurs on Monday.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 13 to 21 deg. F.
Max. temperature: 17 to 23 deg. F.
Average ridgetop wind direction: NE shifting to SW
Average ridgetop wind speed: NE 23 mph | SW 30 mph
Maximum ridgetop wind gust: NE 41 mph | SW 51 mph
New snowfall: 0 inches
Total snow depth: 33 to 58 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Saturday Saturday Night Sunday
Weather: Partly cloudy skies becoming mostly cloudy. A slight chance of snow showers in the afternoon. Mostly cloudy skies, becoming partly cloudy. A slight chance of snow showers in the evening. Sunny skies, becoming partly cloudy.
Temperatures: 27 to 32 deg. F. 12 to 17 deg. F. 33 to 38 deg. F.
Mid Slope Winds: SW to W W SW
Wind Speed: 15 to 20 mph with gusts to 40 mph, increasing to 20 to 30 mph with gusts to 60 mph in the afternoon. 15 to 25 mph with gust to 50 mph in the evening, decreasing to 10 to 20 mph. 10 to 15 mph with gusts to 40 mph.
Expected snowfall: Up to 2 Up to 1 0
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Partly cloudy skies becoming mostly cloudy. A slight chance of snow showers in the afternoon. Mostly cloudy skies, becoming partly cloudy. A slight chance of snow showers in the evening. Sunny skies, becoming partly cloudy.
Temperatures: 22 to 28 deg. F. 10 to 15 deg. F. 28 to 34 deg. F.
Ridge Top Winds: SW to W W shifting to N SW to W
Wind Speed: 25 to 40 mph. Gusts to 70 mph increasing to 80 mph in the afternoon. 20 to 35 mph. Gusts to 60 mph increasing to 70 mph after midnight. 20 to 30 mph. Gusts to 60 mph decreasing to 50 mph in the afternoon.
Expected snowfall: Up to 2 Up to 1 0
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