THIS AVALANCHE ADVISORY EXPIRED ON February 14, 2016 @ 6:47 am
Avalanche Advisory published on February 13, 2016 @ 6:47 am
Issued by Brandon Schwartz - Tahoe National Forest

LOW avalanche danger is expected today for all elevations and aspects. Human triggered loose wet avalanches could still occur in isolated areas this afternoon on E-SE-S-SW aspects on slopes 37 degrees and steeper. 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: Loose Wet
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  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

The snowpack on E-SE-S-SW aspects has for the most part adjusted to the post storm warming over the past 10 days. E aspects remain somewhat transitional in some areas while melt-freeze conditions have become well established on SE-S-SW aspects. Human triggered loose wet avalanche activity is expected to be more isolated today. This is due to cooler forecast air temperatures and the still relatively lower amounts of incoming solar radiation from the mid February sun.

A decent snow surface refreeze is expected to have occurred last night, still driven mainly by radiational cooling under clear skies as air temperatures in most locations remained above freezing. This snow surface refreeze is expected to remain supportable through the morning hours today. Sometime during the mid day to afternoon hours conditions will become less supportable and loose wet snowpack instability will increase.

Once body weight boot penetration approaches 1 foot deep or more into surface wet snow, change to a more northerly or westerly aspect and/or move to slopes less than 35 degrees in slope angle without steeper terrain above. Planned timing of travel in avalanche terrain is critical for the preferred mix of frozen to melting, but still supportable snow surface conditions.

recent observations

Observations made yesterday on Tamarack Peak (Mount Rose area) and on Angora Peak (Desolation Wilderness area), both revealed that melt-freeze conditions have become fairly well established in the upper snowpack on SE-S-SW aspects. In some areas, E aspects lag a bit behind with a pockety mix of established melt-freeze and still transitional snow. Below 6,500' areas bare ground have started to appear as snow surface melt continues.

On shaded northerly aspects above 8,000' the snow surface has escaped undergoing melt-freeze with softer, colder snow lingering in wind protected areas. Below about 7,500' surface melt-freeze has created surface crusts on northerly aspects. Recent snowpit data from around the forecast area targeting the Jan 29 rain crust(s) in the upper portion of the snowpack have shown some minor near crust faceting, but no problematic weak layers at this time.

Weather and CURRENT CONDITIONS
weather summary

High pressure continues to dominate the weather over the forecast area. A weak weather system will pass to the north tomorrow, shifting and increasing ridgetop winds. Otherwise, maximum daytime air temperatures are expected to cool a few degrees today and tomorrow, but still remain above average. Air temperatures at 6 am this morning were in the upper 30s in most locations. This is a few degrees colder than 24 hours ago. Ridgetop winds have shifted from the SW to W this morning and are expected out of the NW today. Light to occasionally moderate speed NW winds are expected through this evening. Winds are forecast to shift to the NE and become moderate in speed tomorrow morning.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 30 to 40 deg. F.
Max. temperature in the last 24 hours: 46 to 51 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 16 mph
Maximum wind gust in the last 24 hours: 30 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 62 to 76 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. Partly cloudy skies. Partly cloudy skies.
Temperatures: 44 to 51 deg. F. 26 to 32 deg. F. 43 to 50 deg. F.
Wind Direction: W Variable NE
Wind Speed: 10 to 15 mph in the morning, becoming light. Light winds Light winds, increasing to 10 to 15 mph with gusts to 25 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Sunny skies. Partly cloudy skies. Partly cloudy skies.
Temperatures: 39 to 46 deg. F. 23 to 30 deg. F. 38 to 45 deg. F.
Wind Direction: NW NW N to NE
Wind Speed: 15 to 20 mph. Gusts up to 30 mph in the morning. 10 to 15 mph with gusts to 25 mph. 10 to 15 mph with gusts to 25 mph, increasing to 20 to 25 mph with gusts to 35 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.