THIS AVALANCHE ADVISORY EXPIRED ON February 1, 2015 @ 6:45 am
Avalanche Advisory published on January 31, 2015 @ 6:45 am
Issued by Brandon Schwartz - Tahoe National Forest

Avalanche danger remains LOW for all elevations and aspects.

Normal caution is advised.

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
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Snowpack instability concerns for today are minimal. NE ridgetop winds that increased last night have very little snow available for wind transport following the NE wind event on Jan 28. Windward areas above treeline are already scoured back down to rain crust, so no new wind slabs of significance are expected to form in lee areas. These same winds will slow the rate of snow surface melt in areas exposed to both wind and sun. Sun exposed areas protected from the NE winds will experience more snow surface melt today, but only minimal wet snow instability is expected. Isolated areas of human triggered roller balls, pinwheels, and loose wet sluffs are not impossible today, but the expected small size should not present a significant hazard to backcountry travelers. Exercise normal caution while traveling in the backcountry and reevaluate terrain choice if signs of instability are observed. 

recent observations

Observations made yesterday on Incline Lake Peak (Mount Rose area) revealed recent new snow amounts of 5 inches in wind protected areas below treeline. On northerly aspects, this snow remained unconsolidated. In sun exposed areas on SE-S aspects, melt-freeze had begun to influence the snow surface. Snowpit data collected in below treeline terrain on a N aspect, 32 degree slope at 9,140' revealed a snowpack that is clearly well into the stages of rounding, but still retains residual faceted properties more so than other locations around the forecast area. Snowpit tests indicated very good stability with propagation unlikely along any of the relative weak layers below the near surface rain crust. No informal signs of instability were observed in this area. Wet surface snow up to 0.5 inches deep was observed on SE aspects at 8,600' at 11:30 am. By 1:15 pm, these same areas were beginning to refreeze under cloudy skies.

Weather and CURRENT CONDITIONS
weather summary

High pressure is building over the forecast area. Lingering cloud cover south of Hwy 50 this morning is expected to clear during the morning hours. Sunny skies and above average air temperatures are forecast for the next several days. Gusty northeast ridgetop winds this morning are expected to decrease as the day progresses. Expect ridgetop gusts to 55 mph during the morning hours. Air temperatures between 6,000' and 10,000' are in the upper teens to mid 20s this morning with minimal inversion conditions. Maximum daytime air temperatures are forecast to reach the upper 30s to mid 40s today for areas above 7,000'. For Sunday, a weak weather system will pass to the north of the forecast area. Expect partly cloudy skies, light west winds, and a daytime air temperature increase of 5 to 10 degrees.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 19 to 26 deg. F.
Max. temperature in the last 24 hours: 35 to 38 deg. F.
Average wind direction during the last 24 hours: Northeast
Average wind speed during the last 24 hours: 31 mph
Maximum wind gust in the last 24 hours: 57 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 23 to 33 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Saturday Saturday Night Sunday
Weather: Sunny skies. Clear skies. Partly cloudy skies.
Temperatures: 37 to 44 deg. F. 27 to 33 deg. F. 48 to 54 deg. F.
Wind Direction: NE Variable Variable
Wind Speed: 20 to 30 mph. Gusts up to 45 mph decreasing to 35 mph in the afternoon. Light winds Light winds
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Sunny skies. Clear skies. Partly cloudy skies.
Temperatures: 36 to 43 deg. F. 26 to 33 deg. F. 41 to 48 deg. F.
Wind Direction: NE E W
Wind Speed: 30 to 40 mph with gusts to 55 mph, decreasing to 15 to 25 mph with gusts to 45 mph in the afternoon. 10 to 15 mph. Gusts to 25 mph in the evening. 10 to 15 mph with gust to 25 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.