Avalanche Advisory: Friday - Dec 28, 2018

THIS AVALANCHE ADVISORY EXPIRED ON December 29, 2018 @ 6:36 am
Avalanche Advisory published on December 28, 2018 @ 6:36 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

Natural and human triggered avalanches will be unlikely today.  However, it would not be impossible for a person to find a small isolated fresh wind slab on W-S-SE facing terrain at mid to upper elevations due to extreme NE ridge-top winds last night and strong N winds today. Early season obstacles exist!  

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Avalanche Problem 1: Wind Slab
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NE ridge-top winds were howling last night with gusts recorded over 110mph on top of Mammoth Mtn.  Upper elevation N Winds are expected to continue today in the 80mph range. 1-2” of very low-density snow fell in the last 24 hours, at least around the mammoth area.  While most of this new snow, and the limited amounts of loose snow that existed on the ground on exposed slopes prior likely got blown or will get blown into the atmosphere, some small wind deposits could form on W-S-SE facing mid to upper elevation slopes.  Watch for isolated patches of fresh dense snow that could be sensitive to a human trigger especially in complex terrain where a fall could have bad consequences.  Continue practicing safe travel protocols such as exposing one person at a time.

advisory discussion

4-6” of new snow fell Christmas Eve night with strong SW winds.  Over the last 3 days the winds have shifted around the compass to the N and NE, turning exposed slopes at mid to upper elevations on all aspects into a patchwork of scour and firm wind deposit.  The cold and clear conditions thru the new-year will continue to facet and weaken our thin snowpack.  While not a stability concern now, it could become a concern if we do get a significant dump later in January.  

Besides avalanches, early season obstacles are a very real concern, as well as firm slopes and cold temperatures!  Bundle up and be careful. 

Weather and CURRENT CONDITIONS
weather summary

Wind and COLD is on tap for today, with flurries in the morning ending in sunny skies for the afternoon.  Expect highs only in the teens above 10,000’, upper elevation N winds gusting into the 80s, and lows in the single digits tonight.

Saturday and Sunday will warm up to average, before another cold front drops temperatures again Sunday night thru New Years.  Maybe some snow on tap for the second week of January (fingers crossed)?

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy then becoming sunny. Isolated snow showers in the morning. Snow levels below 7000 feet. Chance of precipitation is 15%. Clear. Sunny.
Temperatures: 17 to 23. deg. F. 2 to 8. deg. F. 34 to 39. deg. F.
Mid Slope Winds: North 15 to 25 mph. Gusts up to 80 mph decreasing to 60 mph in the afternoon. North 15 to 25 mph with gusts to 50 mph. North 10 to 15 mph with gusts to 45 mph in the morning becoming light.
Expected snowfall: trace in. 0 in. 0 in.
Over 10,000 ft.
Friday Friday Night Saturday
Weather: Partly cloudy then becoming sunny. Isolated snow showers in the morning. Snow levels below 7000 feet. Chance of precipitation is 15%. Clear. Sunny.
Temperatures: 15 to 21. deg. F. 2 below to 3 above zero. deg. F. 30 to 35. deg. F.
Ridge Top Winds: North 40 to 60 mph decreasing to 30 to 50 mph in the afternoon. Gusts up to 85 mph. North 30 to 45 mph with gusts to 65 mph. North 25 to 40 mph shifting to the northeast 20 to 30 mph in the afternoon. Gusts up to 60 mph.
Expected snowfall: trace 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 Snowpack Summary is provided by the Eastern Sierra Avalanche Center, who is solely responsible for its content.

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