Avalanche Advisory: Wednesday - Jan 15, 2020

THIS AVALANCHE ADVISORY EXPIRED ON January 16, 2020 @ 4:34 am
Avalanche Advisory published on January 15, 2020 @ 4:34 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

Low avalanche danger continues today at all elevations.  Be on the lookout for a small isolated windslab in consequential terrain.  Use extra caution traveling on exposed slopes at all elevations due to widespread firm challenging surface conditions. 

 

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
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

SW winds were extreme yesterday and will continue today at strong levels.  Despite very little loose snow available for transport, keep your eyes out for a small isolated fresh windslab in consequential terrain.  Triggering even a small plate could be enough to knock a rider off balance and lead to an unarrestable fall.  

 
advisory discussion

No new snow has fallen for over two weeks.  Very strong winds during this time have wreaked havoc on surface conditions for exposed slopes at all elevations.  Slide-for-life wind-board and melt-freeze crusts are widespread, as are breakable crusts and sastrugi.  Low elevation sheltered trees continue to harbor loose faceted surface snow.   With the incoming storm on Thursday, keep in mind how new snow may bond … or not … to this wide-array of surface conditions.  Underlying weak faceted snow layers which exist in some areas may become concerning as well.      

 
Weather and CURRENT CONDITIONS
weather summary

One more day of dry weather is on tap for today. Expect mostly sunny to partly cloudy skies, highs near freezing around 10,000’, and much decreased but still strong winds continuing to gust out of the SW up to 60mph in the afternoon over ridge tops.

 

We will finally see some new snow tomorrow, with the first storm of 2020 making its way down from the Gulf of Alaska. The incoming storm is slowing down and is now expected to impact our area most heavily Thursday afternoon and evening.  A Winter Weather Warning is in effect from noon on Thursday to 1am Friday morning, with 8-18” of snow likely before midnight Thursday, with greatest amounts projected near Mammoth. 

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: Partly cloudy then becoming mostly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%. Partly cloudy then becoming cloudy. Chance of snow in the morning, then snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 95%.
Temperatures: 32 to 40. deg. F. 19 to 24. deg. F. 26 to 34. deg. F.
Mid Slope Winds: Southwest around 15 mph. Gusts up to 35 mph increasing to 50 mph in the afternoon. South 15 to 30 mph with gusts to 60 mph. South 20 to 35 mph increasing to 30 to 40 mph in the afternoon. Gusts up to 70 mph.
Expected snowfall: 0 in. 0 in. 80% probability of 2 to 8 inches. 20% probability 8 to 12 inches. | SWE = 0.25-0.50 inch. in.
Over 10,000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny then becoming partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 5%. Mostly cloudy. Chance of snow in the morning, then snow in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 100%.
Temperatures: 24 to 32. deg. F. 13 to 18. deg. F. 17 to 25. deg. F.
Ridge Top Winds: Southwest 20 to 35 mph. Gusts up to 45 mph increasing to 60 mph in the afternoon. Southwest 30 to 45 mph with gusts to 70 mph. South 40 to 60 mph with gusts to 80 mph.
Expected snowfall: 0 in. 0 in. 80% probability of 3 to 10 inches. 20% probability of 8 to 15. | SWE = 0.30-0.55 inch. 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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