THIS AVALANCHE FORECAST EXPIRED ON April 20, 2020 @ 7:00 am
Avalanche Forecast published on April 19, 2020 @ 7:00 am
Issued by Andy Anderson - Tahoe National Forest - Sierra Avalanche Center

Spring weather with some sunshine should provide enough warming for avalanches of loose wet snow to become possible on steep slopes again today. Slabs of wet snow may also still warrant concern in some areas. The avalanche danger is MODERATE today. 

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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Below freezing temperatures and partly clear skies should have allowed some of the wet snow to refreeze last night. Periods of sun this morning combined with daytime warming and a slight chance for afternoon showers should melt through the refreeze today. Once this refreeze melts, deep wet snow will exist on many slopes, and loose wet avalanches will become possible on steep slopes. Some of these could entrain enough snow to bury a person. 

Snow conditions can change quickly and go from supportable in the morning to wet and loose in a short period of time. As soon as the snow starts to get wet and lose its ability to support a person, it is time to move to lower angle terrain or get off the wet snow. 

Avalanche Problem 2: Wet Slab
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Observations indicate that the buried surface hoar layer is starting to assimilate into the snowpack. Still, with all of the uncertainty associated with forecasting wet slab avalanches, this problem will remain a concern for a little while longer. If a wet slab avalanche does occur, it could involve enough snow to bury or injure a person.

Using timing and terrain to avoid wet snow and/or steep terrain can help avoid wet slabs.

recent observations
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Small loose wet avalanches were reported on Mt. Judah, in the Mt. Houghton area, and in the Elephant's Graveyard area yesterday. Widespread roller balls also occurred in these areas.

Observers reported 1-2 inches of new snow on top of old wet snow on Mt. Judah; up to 3 inches of new snow on top of wet snow in Elephant's Graveyard; and 1 to 3 inches of new snow on top of wet snow in the Mt. Rose backcountry. Observers also reported that the new snow became wet and sticky with "punchy" travel conditions due to sinking into the old wet snow before 11 am yesterday.

Observations in wind-exposed places like Mt. Houghton and Elephant's Graveyard did not find large new wind slabs. One drift up to 12 inches deep with some minor cracking was noted on Mt. Houghton, and some minor cracking occurred on a small cornice in the Elephant's Graveyard area. 

Weather and CURRENT CONDITIONS
weather summary

Above 7500 ft. most sensors reported overnight temperatures that remained below freezing. Cloud cover also decreased during the night and some areas saw clear skies. The forecast calls for some lingering clouds this morning with periods of sunshine. An increase in cloud cover is expected in some places this afternoon. Tomorrow should see a weak system move through the area bringing more clouds and a chance for some light precipitation in the afternoon. 

CONDITIONS ALONG THE SIERRA CREST BETWEEN 8200 FT. AND 9200 FT. IN THE LAST 24 HOURS
Weather Station Map
Weather Station Table
6am temperature: 25 to 31 deg. F.
Max. temperature: 41 to 47 deg. F.
Average ridgetop wind direction: SW
Average ridgetop wind speed: 20 to 25 mph
Maximum ridgetop wind gust: 44 mph
New snowfall: trace to 0 inches
Total snow depth: 54 to 77 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Sunday Sunday Night Monday
Weather: Partly cloudy. Snow levels below 7000 feet increasing to 7500 feet in the afternoon. Chance of precipitation is 10%. Partly cloudy. Snow levels 7500 feet decreasing to below 7000 feet after midnight. Chance of precipitation is 5%. Mostly cloudy. Scattered showers in the afternoon. Snow levels around 7000 feet. Chance of precipitation is 40%.
Temperatures: 42 to 48 deg. F. 25 to 30 deg. F. 41 to 47 deg. F.
Mid Slope Winds: Southwest 10 to 15 mph with gusts to 25 mph. Southwest around 15 mph with gusts to 25 mph in the evening becoming light. Light winds.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. little or no accumulation. | SWE = less than 0.10 inch.
For 8000 ft. to 9000 ft.
Sunday Sunday Night Monday
Weather: Partly cloudy. Snow levels below 7000 feet increasing to 7500 feet in the afternoon. Chance of precipitation is 10%. Partly cloudy. Snow levels 7500 feet decreasing to below 7000 feet after midnight. Chance of precipitation is 5%. Mostly cloudy. Scattered snow showers in the afternoon. Snow levels around 7000 feet. Chance of precipitation is 45%.
Temperatures: 34 to 42 deg. F. 22 to 27 deg. F. 35 to 41 deg. F.
Ridge Top Winds: Southwest 20 to 35 mph. Gusts up to 50 mph decreasing to 40 mph in the afternoon. West 15 to 25 mph in the evening becoming light. Light winds.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. less than 1 inch. | SWE = less than 0.10 inch.
Disclaimer

This avalanche forecast is provided through a partnership between the Tahoe National Forest and the Sierra Avalanche Center. This forecast 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 forecast applies only to backcountry areas outside established ski area boundaries. This forecast describes general avalanche conditions and local variations always occur. This forecast expires 24 hours after the posted time unless otherwise noted. The information in this forecast is provided by the USDA Forest Service who is solely responsible for its content.

For a recorded version of the avalanche forecast call (530) 587-3558 x258