THIS AVALANCHE FORECAST EXPIRED ON April 4, 2019 @ 6:58 am
Avalanche Forecast published on April 3, 2019 @ 6:58 am
Issued by Steve Reynaud - Tahoe National Forest

MODERATE avalanche danger will exist today due to loose wet and wind slab avalanche problems.  Human triggered avalanches remain possible.

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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As daytime warming occurs, loose wet avalanche activity will become possible on all aspects and elevations.  Overnight cloud cover with some areas below 7500' having above freezing temperatures could cause loose wet avalanches to occur earlier than areas that had a good overnight refreeze.  Large loose wet avalanches are possible that involve the recent storm snow and potentially the underlying wet snow.  Size D2 loose wet avalanches occurred yesterday that traveled long distances.  

Monitor snow surface conditions and warming.  Roller balls and pinwheels will be an indication that the snow surface is losing strength and larger loose wet avalanches could occur. 

 

Avalanche Problem 2: Wind Slab
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Recently formed wind slabs could still be reactive on NW-N-NE-E-SE aspects in near and above treeline terrain.  Due to the wet and heavy recent storm snow, most wind transport is limited to areas above 8000' where colder snow exists.  Continued moderate to strong SW winds will transport snow until winds decrease later today.  Daytime warming could further weaken these newly formed wind slabs

Look for evidence of recent snow transport including blowing snow, new cornice formation, and wind pillows.  Use terrain to avoid areas of concern.

recent observations

*  Multiple loose wet avalanches were reported from Donner Peak and Andesite Peak in the Donner Summit area up to size D2.  These avalanches involved all the new storm snow and some of the underlying wet snow.

*  Heavy storm snow existed above wet snow in the Echo Lakes area and the Donner Summit area up to 8000'.  Minimal wind transport was observed below 8000' due to the heavy storm snow.  Snow level stayed around 7000' throughout the day.

Weather and CURRENT CONDITIONS
weather summary

Recent storm totals of 5-12'' of snow along the Sierra Crest above 8000' and up to 9'' in the Mt. Rose area.  Snow levels hovered around 7000' for most of the storm before cooling off last night.  A break in the weather is expected today with near average spring temperatures.  SW winds have been in the moderate to strong range for most of this storm and are forecasted to decrease today.  Cloud cover is expected to increase into the afternoon today to mostly cloudy skies.  Another couple small spring storms are forecasted for Thursday and Friday.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 25 to 29 deg. F.
Max. temperature in the last 24 hours: 30 to 38 deg. F.
Average wind direction during the last 24 hours: SW
Average wind speed during the last 24 hours: 25 to 35 mph
Maximum wind gust in the last 24 hours: 58 mph
New snowfall in the last 24 hours: 3 to 7 inches
Total snow depth: 117 to 163 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 then becoming mostly cloudy. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 5%. Mostly cloudy. Snow levels 7500 feet. Chance of precipitation is 5%. Cloudy. Chance of showers. Snow levels 7000 feet. Chance of precipitation is 50%.
Temperatures: 43 to 49. deg. F. 27 to 32. deg. F. 39 to 45. deg. F.
Mid Slope Winds: Light winds. Light winds. Southwest 10 to 20 mph. Gusts up to 40 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. 70% probability up to 1 inch. 30% probability up to 3 inches. | SWE = less than 0.10 inch.
For 8000 ft. to 9000 ft.
Wednesday Wednesday Night Thursday
Weather: Partly cloudy then becoming mostly cloudy. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 5%. Mostly cloudy. Snow levels 7500 feet. Chance of precipitation is 5%. Cloudy. Chance of snow showers in the afternoon. Snow levels 7000 feet. Chance of precipitation is 50%.
Temperatures: 39 to 45. deg. F. 24 to 29. deg. F. 35 to 41. deg. F.
Ridge Top Winds: Southwest 10 to 15 mph. Southwest 10 to 20 mph. Gusts up to 35 mph. South-Southwest 20 to 30 mph with gusts to 50 mph.
Expected snowfall: No accumulation. | SWE = none. No accumulation. | SWE = none. 70% probability up to 1 inch. 30% probability up to 3 inches. | 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