THIS AVALANCHE FORECAST EXPIRED ON April 11, 2018 @ 6:51 am
Avalanche Forecast published on April 10, 2018 @ 6:51 am
Issued by Brandon Schwartz - Tahoe National Forest

Areas of MODERATE avalanche danger exist above, near, and below treeline. Poor conditions for snow surface refreeze occurred last night. Avoid travel in or below avalanche terrain in areas where the snow surface is marginally unsupportable to unsupportable wet snow.

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Near Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

2. Moderate

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Below Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Loose Wet
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Air temperatures were in the 40s for most terrain within the forecast area last night with mid to upper 30s at the highest elevations. Periods of cloud cover last night will have also contributed to less than optimal conditions for snow surface refreeze. With the combination of unusually warm overnight air temperatures and some cloud cover, snow surface refreeze last night is expected to be weak in some areas and nonexistent in other areas. Total amounts of snow surface melt will be tempered today by increasing cloud cover and wind, but the snowpack already has a significant head start this morning on becoming unsupportable wet snow.

Areas of loose wet avalanche problems will be possible today on all aspects. Some of the highest elevation NW-N-NE aspects may or may not have better stability depending on areas of localized cloud cover last night. Avalanche size up to D2 is possible (large enough to bury or injure a person). Monitor snow surface supportability.  Avoid travel in or below avalanche terrain in areas where the snow surface is marginally unsupportable to unsupportable wet snow.

recent observations
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* Observations made yesterday morning on Andesite Peak (Donner Summit area) revealed a decent snow surface refreeze on open slopes in the 7,200' to 8,200' elevation range and significantly less snow surface refreeze under forest canopy. The snow surface had entered melt phase by 8:30 am in sun exposed areas.

* Numerous recently opened glide cracks were noted on Sunday in the Desolation Wilderness in areas where the snowpack overlies granite slabs.

Weather and CURRENT CONDITIONS
weather summary

Weather systems will continue to move through the forecast area for the next several days. Precipitation amounts today and tomorrow are rather minimal. Cloud cover, wind, and warm air temperatures will be the most significant weather effects. Air temperatures are well above freezing this morning at all elevations with 40s in the 7,000' to 9,000' elevation range. Cloud cover will increase today with a chance of showers this afternoon through tomorrow. Ridgetop winds shifted to the SW yesterday afternoon and are moderate to strong in speed this morning. Periods of gale force SW winds are forecast for this afternoon. Similar conditions will occur tomorrow with a 5 to 10 degree drop in maximum daytime air temperatures. Significant snowfall is possible Wednesday night into Thursday.

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 40 to 46 deg. F.
Max. temperature: 55 to 60 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 27 mph
Maximum ridgetop wind gust: 69 mph
New snowfall: 0 inches
Total snow depth: 52 to 89 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy skies. Scattered rain showers in the afternoon. Snow level 8,500'. Mostly cloudy skies, becoming partly cloudy. Scattered rain and snow showers in the evening. Snow level 8,000'. Partly cloudy skies, becoming mostly cloudy. A chance of rain and snow showers in the afternoon. Snow level 7,000' to 7,500'.
Temperatures: 48 to 56 deg. F. 31 to 36 deg. F. 40 to 48 deg. F.
Mid Slope Winds: SW SW SW
Wind Speed: 15 to 25 mph with gusts to 35 mph, increasing to 20 to 35 mph with gusts to 55 mph in the afternoon. 20 to 30 mph. Gusts to 60 mph decreasing to 40 mph after midnight. 15 to 20 mph with gusts to 40 mph, increasing to 20 to 30 mph with gusts to 55 mph in the afternoon.
Expected snowfall: 0 0 to 1 Up to 1
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Mostly cloudy skies. Scattered rain and snow showers in the afternoon. Snow level 8,500'. Mostly cloudy skies, becoming partly cloudy. Scattered rain and snow showers in the evening. Snow level 8,000'. Partly cloudy skies, becoming mostly cloudy. A chance of snow showers in the afternoon. Snow level 7,000' to 7,500'.
Temperatures: 43 to 51 deg. F. 30 to 35 deg. F. 35 to 43 deg. F.
Ridge Top Winds: S to SW SW SW
Wind Speed: 30 to 45 mph with gusts to 70 mph, increasing to 35 to 55 mph with gusts to 90 mph in the afternoon. 30 to 50 mph with gusts to 80 mph, decreasing to 25 to 35 mph with gusts to 60 mph after midnight. 25 to 35 mph with gusts to 75 mph, increasing to 30 to 45 mph with gusts to 85 mph in the afternoon.
Expected snowfall: 0 to 1 Up to 1 Up to 1
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