THIS AVALANCHE ADVISORY EXPIRED ON April 13, 2016 @ 6:58 am
Avalanche Advisory published on April 12, 2016 @ 6:58 am
Issued by Andy Anderson - Tahoe National Forest

Loose wet avalanches will remain possible all day today on slopes steeper than 35 degrees on all aspects and elevations. These loose wet avalanches will keep the avalanche danger at MODERATE for today.  Some of the loose wet avalanches could involve enough snow to threaten backcountry travelers. Evaluate snow and terrain carefully. Identify and avoid the areas where unsupportable deep wet snow exists. 

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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  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Another cloudy night with mostly above freezing temperatures means that most areas did not refreeze last night, and any areas where temperatures did dip below freezing will have only experienced a weak refreeze. Another day of temperatures in the 40's above 8000 ft. and low 50's above 7000 ft. combined with some sunshine will allow the wet snow to persist on all aspects and at all elevations. In areas that did receive new snow during the last round of precipitation, the new snow will also become wet and lose its cohesion as it warms up again today. Loose wet avalanches will remain possible today on slopes steeper than 35 degrees. Most of the loose wet avalanches should remain small but some of them could entrain enough snow to pose a threat to backcountry travelers especially in areas where new snow exists or where deep wet snow exists. Even though loose wet avalanches will represent the main avalanche problem today, other unlikely wet snow instabilities like wet slabs or glide avalanches are not impossible. 

Since little to no refreeze occurred last night, deep wet snow that may not support a person will already exist on many slopes this morning. Stepping off your equipment and sinking into wet snow above your boot tops and small surface instabilities like roller balls, pinwheels, or point releases can provide clues that enough wet snow has formed for larger loose wet avalanches to become an issue. Terrain traps like gullies, creeks, and cliffs can greatly increase the risk of any size loose wet avalanches.

recent observations

Rain soaked wet snow existed on all aspects and elevations of Donner Peak yesterday. This wet snow measured between ankle deep and just over boot top deep, but it could still barely support a skier as of 10:30 am. Ski cuts on steep test slopes triggered shallow loose wet sluffs and some larger loose wet point releases had occurred on the E and NE faces of Donner Peak and Mt. Judah between Sunday and Monday. Observations indicated that well established drainage channels exist in the snowpack. 

Weather and CURRENT CONDITIONS
weather summary

Some scattered showers brought additional rain to some parts of the region yesterday. The cloud cover remained over the mountains last night. Cloud cover should remain scattered over the forecast area this morning before cumulus clouds start to rebuild across the mountains this afternoon. These clouds should not produce additional showers except in the far north of the forecast area where a slight chance of afternoon showers exists for this afternoon. The forecast calls for more temperatures in the upper 40's above 7000 ft. today and tomorrow. Cloud cover should diminish this evening before increasing again tomorrow. The southwest wind should also start to increase today. These increasing southwest winds and tonight's/tomorrow's increasing cloud cover are a result of a storm system approaching the area tomorrow night. The details of this system remain uncertain. For more updates check in with the Reno NWS.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 31 to 38 deg. F.
Max. temperature in the last 24 hours: 43 to 47 deg. F.
Average wind direction during the last 24 hours: West to southwest
Average wind speed during the last 24 hours: 10 to 15 mph
Maximum wind gust in the last 24 hours: 26 mph
New snowfall in the last 24 hours: Rain: 0 to .1 inches
Total snow depth: 64 to 103 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Tuesday Tuesday Night Wednesday
Weather: Partly cloudy becoming mostly cloudy Mostly cloudy becoming partly cloudy Mostly cloudy
Temperatures: 47 to 53 deg. F. 30 to 36 deg. F. 42 to 48 deg. F.
Wind Direction: Southwest Southwest Southwest
Wind Speed: 0 to 5 mph in the morning increasing to 10 to 15 mph with gusts to 25 mph in the afternoon 15 to 25 mph with gusts to 35 mph 20 to 30 mph with gusts to 35 mph increasing to 45 mph in the afternoon
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Tuesday Tuesday Night Wednesday
Weather: Partly cloudy becoming mostly cloudy Mostly cloudy becoming partly cloudy Mostly cloudy
Temperatures: 39 to 46 deg. F. 30 to 36 deg. F. 38 to 44 deg. F.
Wind Direction: Southwest Southwest Southwest
Wind Speed: 15 to 20 mph with gusts to 30 mph in the afternoon 25 to 35 mph with gusts to 50 mph 30 to 35 mph with gusts to 55 mph increasing to 40 to 45 mph with gusts to 70 mph in the afternoon
Expected snowfall: 0 in. 0 in. 0 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