THIS AVALANCHE ADVISORY EXPIRED ON February 2, 2017 @ 6:57 am
Avalanche Advisory published on February 1, 2017 @ 6:57 am
Issued by Brandon Schwartz - Tahoe National Forest

LOW avalanche danger continues today for all elevations. Isolated areas of instability may exist. Normal caution is advised. Avalanche danger is expected to increase Thursday morning.

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

Ridgetop winds have been moderate speed out of the SW for the past 24 hours drifting very minor amounts of old snow. Blowing snow amounts may increase slightly with increasing wind speeds today. However, new wind slabs of any significant size are not expected to exist in the backcountry today. Cloud cover combined with some mixing out of the air temperature inversion is expected to reduce warming at the mid and upper elevations today by a few degrees. Lesser amounts of snow surface melt on SE-S-SW aspects is expected to occur today compared to what has occurred over the past three days.

Despite the expected good snowpack stability in the backcountry today, expose only one person at a time to steep slopes and do not group up in low angle areas with connected steeper terrain above (avalanche runout zones). Avoid traveling near cornice edges or stopping below cornice features as large sections of cornice collapse can occur. Large horizontal cracks exist in isolated areas due to snowpack creep. These deep cracks can be covered by thin weak snow bridges presenting an additional fall hazard. See the recent observations section below for more info.

recent observations

Observations made yesterday on Waterhouse Peak (Luther Pass area) matched well with other observations from around the forecast area over the last several days. From an avalanche standpoint, the existing snowpack is in good condition to handle new snow loading from the upcoming storm cycle. Some melt has occurred over the past few days on SE-S-SW aspects. Significant amounts of settlement have occurred on NW-N-NE aspects over the past week. Non avalanche specific hazards such as large cornices, rockfall entraining wet loose snow (photo), and deep cracks associated with snowpack creep (video) exist within the forecast area.

Weather and CURRENT CONDITIONS
weather summary

Transitional weather will occur today with cloudy skies and increasing SW winds ahead of an approaching storm system. Precipitation is expected to begin late tonight. A period of high intensity precipitation is expected tomorrow morning. A lull in precipitation is forecast to occur on Thursday afternoon before intensity picks back up late Thursday night into Friday. Snow level is expected to rise to 7,000' Thursday afternoon and then gradually lower to around 6,000' late Friday. For the latest thinking on this approaching storm system, please see the Winter Storm Warning from NWS Reno.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 30 to 37 deg. F.
Max. temperature in the last 24 hours: 40 to 48 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 26 mph
Maximum wind gust in the last 24 hours: 48 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 100 to 125 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy skies. Cloudy skies. A slight chance of snow in the evening, then a chance of snow after midnight. Cloudy skies, becoming mostly cloudy. Snow, possibly mixing with rain at 7,000' in the afternoon.
Temperatures: 38 to 48 deg. F. 25 to 30 deg. F. 30 to 37 deg. F.
Wind Direction: SW S S
Wind Speed: 10 to 20 mph with gusts to 35 mph. 10 to 20 mph with gusts to 35 mph. 15 to 25 mph with gusts to 40 mph.
Expected snowfall: 0 in. Up to 1 in. 3 to 5 in.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy skies. Cloudy skies. A slight chance of snow in the evening, then a chance of snow after midnight. Cloudy skies with snow, becoming mostly cloudy.
Temperatures: 32 to 42 deg. F. 22 ot 27 deg. F. 27 to 31 deg. F.
Wind Direction: SW S SW
Wind Speed: 20 to 30 mph. Gusts to 50 mph increasing to 70 mph. 20 to 35 mph. Gusts to 70 mph increasing to 85 mph after midnight. 30 to 45 mph with gusts to 90 mph.
Expected snowfall: 0 in. Up to 2 in. 5 to 8 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.

For a recorded version of the Avalanche Advisory call (530) 587-3558 x258