THIS AVALANCHE ADVISORY EXPIRED ON April 13, 2017 @ 6:52 am
Avalanche Advisory published on April 12, 2017 @ 6:52 am
Issued by Brandon Schwartz - Tahoe National Forest

For most of today, avalanche danger is LOW for all elevations. Following arrival of the incoming storm, avalanche danger will increase to CONSIDERABLE during the evening and overnight hours at all elevations. Dangerous conditions will exist in the backcountry tonight and tomorrow with wind slab and storm slab avalanche problems expected.

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

Prior to the onset of intense snowfall this evening or tonight, no specific avalanche problems are expected today. Any areas of wet snow encountered should be evaluated for the unlikely potential of loose wet avalanche problems. Any above treeline or near treeline areas of recently wind drifted or wind loaded snow should be evaluated for the unlikely potential of wind slab avalanche problems.

Exercise normal caution while traveling in or below avalanche terrain by employing accepted best practices for travel in avalanche terrain. This includes communicating within the group to clearly identify slopes of concern, exposing only one person at a time to slopes of concern, and moving from identified safe zone to identified safe zone.

Dangerous avalanche conditions are expected to develop at all elevations this evening, through the overnight hours, and continue well into Thursday. The approaching storm is expected to create widespread wind slab and storm slab avalanche problems.

recent observations

Observations were made yesterday on Incline Lake Peak (Mount Rose area) and on Armstrong Pass (near Freel Peak). Melt-freeze crusts are widespread on the snow surface in most areas. Isolated patches of unconsolidated snow linger from the last storm in shaded areas, generally on northerly aspects. Areas of wet snow were reported yesterday in the Armstrong Pass area below 9,000' with no signs of loose wet instabilities. On Incline Lake Peak, snowpit data collected adjacent to a small (size D1) wind slab avalanche that appeared to have occurred on April 10 produced mixed results with minimal evidence indicating any potential ongoing wind slab instability.

Weather and CURRENT CONDITIONS
weather summary

A warm, windy, and cloudy day is expected today ahead of an approaching storm system. Very light rain and snow is expected to begin after 2 pm this afternoon with snow level 7,000' to 7,500'. Precipitation intensity is expected to increase significantly overnight into Thursday morning with snow level dropping to around 6,000'. Ridgetop winds are out of the SW this morning at gale force speed with gusts over 100 mph. Gale force SW winds are expected to continue through tonight, decreasing to strong in speed tomorrow afternoon. The storm system is expected to taper off around mid day tomorrow with snow showers in the afternoon. Short lived high pressure builds over the region on Friday.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 30 to 34 deg. F.
Max. temperature in the last 24 hours: 34 to 39 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 65 mph
Maximum wind gust in the last 24 hours: 108 mph
New snowfall in the last 24 hours: 0 to trace inches
Total snow depth: 125 to 187 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Wednesday Wednesday Night Thursday
Weather: Partly cloudy skies becoming mostly cloudy. Slight chance of rain and snow in the morning. Chance of rain and snow in the afternoon. Cloudy skies with a chance of rain and snow. Snow after midnight. Cloudy skies with snow showers likely in the morning. Snow showers in the afternoon.
Temperatures: 43 to 49 deg. F. 26 to 31 deg. F. 30 to 35 deg. F.
Wind Direction: SW SW SW
Wind Speed: 15 to 25 mph. Gusts to 50 mph increasing to 70 mph in the afternoon. 25 to 40 mph with gusts to 80 mph. 20 to 30 mph. Gusts to 60 mph decreasing to 40 mph in the afternoon.
Expected snowfall: Up to 1 in. Likely 4 to 8 in. | Low probability of 8 to 12 in. 1 to 5 in.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Partly cloudy skies, becoming mostly cloudy. Slight chance of snow in the morning. Chance snow in the afternoon. Cloudy skies with a chance of snow. Snow after midnight. Cloudy skies with snow showers likely in the morning. Snow showers in the afternoon.
Temperatures: 38 to 44 deg. F. 22 to 28 deg. F. 25 to 31 deg. F.
Wind Direction: SW SW SW
Wind Speed: 25 to 35 mph with gusts to 75 mph, increasing to 30 to 45 mph with gusts to 105 mph in the afternoon. 40 to 60 mph with gusts to 120 mph. 30 to 50 mph with gusts to 100 mph, decreasing to 20 to 35 mph with gusts to 70 mph in the afternoon.
Expected snowfall: Up to 1 in. Likely 5 to 9 in. | Low probability of 9 to 12 in. 1 to 5 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