THIS AVALANCHE FORECAST EXPIRED ON April 21, 2018 @ 6:51 am
Avalanche Forecast published on April 20, 2018 @ 6:51 am
Issued by Brandon Schwartz - Tahoe National Forest

CONSIDERABLE avalanche danger will develop today at all elevations as rapid warming of recent storm snow creates a loose wet avalanche problem. Avoid travel in or below avalanche terrain on slopes with marginally supportable to unsupportable wet snow conditions or on slopes where roller balls are occurring.

3. Considerable

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Above Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Near Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

3. Considerable

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Below Treeline
Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
    Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.
Avalanche Problem 1: Loose Wet
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Today is fairly prime for human triggered loose wet avalanche activity. Rapid warming conditions will affect the recent new snow from April 15-16 that has yet to have had full exposure to previous melt-freeze cycles this past week. Loose wet avalanches will become possible on all aspects at all elevations as daytime warming progresses. Avalanche size up to D2 is possible (large enough to bury or injure a person).

Human triggered roller balls will be an indication that unstable wet snow conditions are developing. E-SE-S-SW-W aspects will hold a short window of supportability this morning on a thin melt-freeze crust. Once the fairly thin melt-freeze crust becomes marginally supportable to unsupportable, recent storm snow below it will become prone to loose wet avalanche activity. NW-N-NE aspect slopes that hold breakable crust over recent storm snow or recent storm snow without a surface crust will go straight to developing a loose wet avalanche problem today. Avoid travel in or below avalanche terrain on slopes with marginally supportable to unsupportable wet snow conditions or on slopes where roller balls are occurring.

recent observations
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* Recent field observations have indicated that the recent new snow from April 15-16 has remained transitional on all aspects. This snow has yet to become fully affected by melt-freeze due to the cloud cover, snow showers, and below average air temperatures this past week.

* Snow cover continues to become thin to nonexistent in the lower elevations of the forecast area. Snowcover improves above 7,200'-8,000' depending on location. Numerous open creeks exist below 8,000'.

Weather and CURRENT CONDITIONS
weather summary

High pressure is building over the forecast area. Sunny skies and decreasing winds are forecast for today into tomorrow. A warming trend starts today as air temperatures jump from 10 to 20 degrees below average this past week to 10 to 15 degrees above average for the next several days.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 24 to 31 deg. F.
Max. temperature: 34 to 38 deg. F.
Average ridgetop wind direction: NE
Average ridgetop wind speed: 21 mph
Maximum ridgetop wind gust: 40 mph
New snowfall: Trace inches
Total snow depth: 50 to 94 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 51 to 56 deg. F. 33 to 38 deg. F. 57 to 62 deg. F.
Mid Slope Winds: NE Variable Variable
Wind Speed: Light winds. Gusts up to 25 mph in the morning. Light winds Light winds
Expected snowfall: 0 0 0
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Sunny skies. Clear skies. Sunny skies.
Temperatures: 47 to 53 deg. F. 33 to 38 deg. F. 52 to 58 deg. F.
Ridge Top Winds: NE Variable Variable
Wind Speed: 15 to 25 mph with gusts to 40 mph. Light winds Light winds
Expected snowfall: 0 0 0
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