Avalanche Advisory: Wednesday - Jan 22, 2020

THIS AVALANCHE ADVISORY EXPIRED ON January 23, 2020 @ 6:59 am
Avalanche Advisory published on January 22, 2020 @ 6:59 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

LOW avalanche danger exists at all elevations.  LOW does not mean NO.  While unlikely, small isolated wind slabs sensitive to a human trigger may exist near tree line and above on northerly to easterly aspects.  Small loose wet sloughs are possible in steep terrain at low elevations as surface snow warms through the day.  

 

1. Low

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Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Near Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1. Low

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Below Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
    Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Wind Slab
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Strong winds have been out of the south to west over the past few days at upper elevations. Despite the limited amount of loose snow available for transport due to the extreme winds that occurred with our last snowfall on Jan 17th, some snow transport has been occurring.  Be on the lookout for small isolated areas of new deposition on the leeward side of ridges or sidewalls of gullies on NW-N-NE-E facing slopes especially around tree line where more snow is available for transport.  Pay attention to cornices and surface snow clues to help identify where these wind deposits may lie.  Greatest concern exists in extreme terrain where a small release could take a rider off their feet and lead to a bad fall.  Loose faceted snow under windslabs could lead to a larger than expected release.   

 
Avalanche Problem 2: Loose Wet
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Warming temperatures and continued cloud cover will result in a green-house effect warming surface snow. Yesterday lower elevation temperatures were well above freezing and snow on even northerly facing shaded terrain was becoming moist. Rollerballs and small loose wet sloughs resulted from ski turns in steeper terrain.  Today temperatures are expected to be ~5°F warmer than yesterday, with continued cloud cover.  Be aware of the increasing potential for small loose wet sloughs at lower elevations especially in steep north facing terrain as slopes warm thru the day.  North facing slopes are of more concern due to the softer snow that exists there, but other aspects could be concerning as well.  Getting caught-up in a small loose wet slide could pull a rider off their feet and lead to a bad fall especially in confined terrain.  

 
advisory discussion

6-12” of new snow fell with extreme winds last Thursday.  Over two weeks of cold clear weather preceded this snowfall which led to a great deal of faceting and weakening of our snowpack in many areas.  While test pits across our range have shown a concerning structure with layers of loose snow under stronger snow, no avalanche activity has occurred since the storm 5 days ago, and the avalanche activity that was reported during the storm did not involve these buried layers.  Had the latest storm been more significant, these layers most likely would have become reactive and we would have seen many more larger avalanches.  But the amount of new snow we received just wasn’t enough to tip the balance.  Since the storm relatively warm temperatures and extended period of cloud cover has led to a strengthening snowpack.  None-the-less, our shallow suspect snowpack structure should be kept in mind and continue to be monitored.  Variability is great across our huge forecast area, and it remains important to take your shovel out and do your own localized assessments.          

 
Weather and CURRENT CONDITIONS
weather summary

For today expect mostly cloudy skies, SW to W winds decreasing through the day gusting into the 40s in the morning, and warmer temperatures reaching the mid 30s around 10,000’.  Dry conditions and a warming trend will continue until a chance of snow returns on Sunday as a storm system moves in mostly north of us.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy. Slight chance of snow in the morning. Snow levels below 7000 feet increasing to 7000 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 0%. Sunny then becoming partly cloudy. Snow levels below 7000 feet increasing to 7000 feet in the afternoon. Chance of precipitation is 5%.
Temperatures: 37 to 43. deg. F. 19 to 24. deg. F. 40 to 46. deg. F.
Mid Slope Winds: Southwest around 15 mph with gusts to 45 mph in the morning becoming light. Light winds. Light winds.
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
Wednesday Wednesday Night Thursday
Weather: Mostly cloudy. Slight chance of snow in the morning. 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 0%. Sunny then becoming partly cloudy. Snow levels below 7000 feet increasing to 7500 feet in the afternoon. Chance of precipitation is 5%.
Temperatures: 30 to 36. deg. F. 17 to 22. deg. F. 32 to 38. deg. F.
Ridge Top Winds: West 15 to 25 mph. Gusts up to 45 mph decreasing to 35 mph in the afternoon. Northwest around 15 mph. West around 15 mph.
Expected snowfall: 0 in. 0 in. 0 in.
Disclaimer
This Avalanche Advisory is designed to generally describe avalanche conditions where local variations always occur. This product only applies to backcountry areas located outside established ski area boundaries. The information in this Avalanche Advisory is provided by the Eastern Sierra Avalanche Center, who is solely responsible for its content.

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