THIS AVALANCHE ADVISORY EXPIRED ON April 19, 2014 @ 7:00 am
Avalanche Advisory published on April 18, 2014 @ 7:00 am
Issued by Andy Anderson - Tahoe National Forest

Pockets of MODERATE danger will form on all aspects at all elevations on slopes 37 degrees and steeper as daytime warming and sunshine melt through the overnight refreeze that holds the snowpack together. Human triggered loose wet avalanches will become possible. Natural avalanches remain unlikely but not impossible.

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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    Very Likely
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Most of the cloud cover cleared out of the skies after 1-2 am last night, and temperatures dropped into the mid to upper 30's. This period of clear skies and cooler overnight lows should have allowed a slightly stronger overnight refreeze. While the intense April sun and daytime highs well above freezing should still melt through this refreeze today, it may last longer due to slightly cooler daytime highs, some expected cloud cover, and the fact that it was a slightly stronger refreeze. Once the refreeze melts, enough unconsolidated wet snow will exist for human triggered loose wet avalanches including pinwheels, roller balls, and loose wet snow point release avalanches to become possible on all aspects at all elevations. Most of these loose wet avalanches should remain small, and they should remain more isolated in distribution today due to the cooler weather and expected cloud cover.

Getting out early and leaving the slopes before last night's refreeze completely melts represents a good way to avoid dealing with unsupportable wet snow. Once the refreeze does melt the recreation conditions deteriorate and the avalanche hazard increases. At that point finding a different afternoon activity that does not involve steep snow covered slopes is a great idea.

recent observations

The snowpack continues to shrink. Remote sensors are reporting about 5 cm of melting each day. Bare ground and rocks that were once snow covered have reappeared. In areas where snow cover remains, deep wet unsupportable snow forms each day as the thin overnight refreezes melt. Yesterday on Becker Peak observations supported these general trends as well. Snow cover has become patchy on the SE-S-SW aspects. By 11:30 am 20 to 30 cm of wet snow existed on the N-NE-E aspects and 15 to 20 cm of wet snow existed on the slightly more supportable SE-S-SW aspects. Ski cuts on steep north facing test slopes did trigger small loose wet snow sluffs that did not entrain very much snow.

Weather and CURRENT CONDITIONS
weather summary

The weak front moving through the region should keep temperatures slightly cooler today and tonight. This front should also bring more cloud cover toady and a 20% chance of isolated showers with some isolated thunderstorms possible this afternoon. Tonight skies should begin to clear back up. The forecast calls for the warmer sunnier weather to return to the area tomorrow.

Weather observations from along the Sierra Crest between 8200 ft. and 8800 ft.
0600 temperature: 34 to 41 deg. F.
Max. temperature in the last 24 hours: 47 to 54 deg. F.
Average wind direction during the last 24 hours: Southwest
Average wind speed during the last 24 hours: 10 to 20 mph
Maximum wind gust in the last 24 hours: 51 mph
New snowfall in the last 24 hours: 0 inches
Total snow depth: 18 to 52 inches
Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 7000 ft. to 8000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy with a 20% chance of isolated showers in the morning and a 20% chance of isolated thunderstorms in the afternoon Mostly cloudy with a 20% chance of isolated thunderstorms in the evening becoming partly cloudy overnight Partly cloudy to mostly sunny
Temperatures: 49 to 56 deg. F. 28 to 38 deg. F. 54 to 60 deg. F.
Wind Direction: Variable Variable Southwest
Wind Speed: Light Light Light increasing to 10 to 15 mph with gusts to 25 mph in the afternoon
Expected snowfall: 0 in. 0 in. 0 in.
For 8000 ft. to 9000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy with a 20% chance of isolated showers in the morning and a 20% chance of isolated thunderstorms in the afternoon Mostly cloudy with a 20% chance of isolated thunderstorms in the evening becoming partly cloudy overnight Partly cloudy to mostly sunny
Temperatures: 44 to 50 deg. F. 28 to 38 deg. F. 45 to 55 deg. F.
Wind Direction: South Southwest Southwest
Wind Speed: 15 to 25 mph in the morning becoming light in the afternoon Light winds increasing to 10 to 15 mph after midnight 15 to 20 mph with gusts to 30 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.