THIS AVALANCHE ADVISORY EXPIRED ON February 15, 2015 @ 6:57 am
Avalanche Advisory published on February 14, 2015 @ 6:57 am
Issued by Andy Anderson - Tahoe National Forest

Avalanche danger should remain LOW for all elevations and aspects again today. Some small loose wet avalanches may become possible on isolated terrain features on slopes 35 degrees and steeper. While larger loose wet avalanches and wet slab avalanches remain unlikely, they are not impossible. Use normal caution when traveling in the backcountry.

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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  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Despite overnight temperatures in the 40's, mostly clear skies should have allowed the snowpack to radiate enough heat for a weak overnight refreeze. Areas north of I-80 where some cloud cover existed last night may not have refrozen. Today's sunny skies and warm temperatures will quickly melt the refreeze, and wet snow instabilities will become possible on all aspects and at all elevations as soon as the refreeze thaws. Human triggered roller balls and pinwheels should represent the majority of the wet snow instability, but some isolated loose wet avalanches may also become possible. In most areas these wet snow issues should remain small and not involve much snow, but isolated larger loose wet avalanches may be possible especially in areas where cloud cover prevented any refreeze last night. Wet slab avalanches remain unlikely, but they are not impossible.

recent observations

Yesterday on Red Lake Peak, northerly aspects above 8500 ft. still held some soft cold snow. In areas below 9500 ft, this soft cold snow only measured a few inches in depth and rested above a very thick and frozen rain crust that wind scouring had exposed in many places. Above 9500 ft. firm wind packed surfaces mixed with areas of softer surface snow existed on the northerly aspects. Snowpit data and general observations did not reveal any signs of instabilities on the northerly aspects.

E-SE-S-SW aspects softened quickly, and some small skier-triggered roller balls and pin wheels did occur on sun-exposed E-SE aspects at around 1 pm. The snow on these aspects had almost been through enough melt-freeze cycles to become corn. It still remained slow and sticky in many areas and will take a few more melt-freeze cycles to fully transition.

Weather and CURRENT CONDITIONS
weather summary

Temperatures remained well above freezing last night with most sensors reporting overnight lows in the 40's above 8000 ft.  Light to moderate southwest winds that started yesterday should continue through today. The weak disturbance that brought the southwest winds also allowed some cloud cover to move into the northern part of the forecast area last night. These clouds should depart by mid morning leaving sunny skies and near record daytime highs again today. The forecast calls for highs in the mid to upper 50's above 7000 ft. Temperatures should cool off some tonight and tomorrow, and daytime highs for tomorrow should only climb into the upper 40's and low 50's above 7000 ft.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 40 to 49 deg. F.
Max. temperature in the last 24 hours: 52 to 58 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 15 mph
Maximum wind gust in the last 24 hours: 30 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 30 to 46 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 becoming sunny Clear Sunny
Temperatures: 54 to 60 deg. F. 24 to 32 deg. F. 45 to 52 deg. F.
Wind Direction: Southwest Variable Variable
Wind Speed: 10 to 15 mph with gusts to 25 mph Light Light
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Saturday Saturday Night Sunday
Weather: Partly cloudy becoming sunny Clear Sunny
Temperatures: 50 to 56 deg. F. 26 to 32 deg. F. 47 to 53 deg. F.
Wind Direction: Southwest Variable East
Wind Speed: 15 to 25 mph with gusts to 35 mph Light 0 to 5 mph increasing to 10 to 15 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.