Avalanche Advisory: Wednesday - Jan 29, 2020

THIS AVALANCHE ADVISORY EXPIRED ON January 30, 2020 @ 7:00 am
Avalanche Advisory published on January 29, 2020 @ 7:00 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

LOW avalanche danger continues at all elevations.  Small isolated wind slabs may be sensitive to a human trigger in extreme terrain at upper elevations.  Continue to monitor the weak underlying snowpack, and always practice safe travel protocols such as exposing one person at a time.   

 

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

Predominant south to west winds shifted directions last night out of the north and northeast and will continue today with gusts into the 60mph range over ridgetops.  Small isolated windslabs may develop in extreme terrain today at upper elevations on NW—>SW—>SE facing slopes, while older stubborn small wind slabs may exist on NW—>NE—>SE.  Limited amounts of loose snow will limit the size and distribution of these slabs. Watch for surface clues and blowing snow to help identify where small slabs may be.  While unlikely to result in a burial, triggering a small slab could result in a bad fall in consequential terrain.   

 
Avalanche Problem 2: Persistent Slab
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Weak underlying faceted layers exist in many areas.  Large collapses and surface cracking over the past week have been alarming, as well as propagating snowpit test results.  While no reported avalanches have occurred, an isolated area may exist where the right combination of a continuous weak layer across a slope with a contiguous slab of thick enough snow above where an avalanche could be triggered.  Take your shovel out to do your own investigation, and make your terrain choices accordingly.  Keep in mind that a persistent slab avalanche could likely fail above you and be larger than expected.           

 
advisory discussion

The weak underlying snowpack continues to be a topic of conversation amongst the forecasters.  While recent observations have failed to find the right combination of structure, contiguous overlying slab, and slope steepness for an avalanche to occur, it’s hard to imagine that all those factors don’t line up just right somewhere out there waiting for a human trigger.  Cold night time temperatures, clear skies, and no significant snow on the horizon won’t help these buried weak layers strengthen.     

 
Weather and CURRENT CONDITIONS
weather summary

For today expect sunny skies, highs near 30°F around 10,000’, and north to northeast winds gusting into the 60s over ridge tops.  Dry conditions continue throughout the week with increasing temperatures peaking on Saturday, before a cold front moves back in dropping temperatures on Sunday with a chance of light snow.

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: Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy. Snow levels below 7000 feet increasing to 8000 feet in the afternoon. Chance of precipitation is 0%.
Temperatures: 31 to 39. deg. F. 23 to 28. deg. F. 38 to 46. deg. F.
Mid Slope Winds: North to northeast 10 to 20 mph with gusts to 35 mph. North to northwest 10 to 20 mph. Gusts to 30 mph in the evening. Northwest around 15 mph with gusts to 35 mph.
Expected snowfall: No accumulation. | SWE = none. in. No accumulation. | SWE = none. in. No accumulation. | SWE = none. in.
Over 10,000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy. Snow levels below 7000 feet. Chance of precipitation is 0%. Partly cloudy. Snow levels 7000 feet increasing to 8500 feet in the afternoon. Chance of precipitation is 0%.
Temperatures: 23 to 31. deg. F. 19 to 24. deg. F. 29 to 37. deg. F.
Ridge Top Winds: North to northeast 20 to 45 mph with gusts to 65 mph. North to northeast 20 to 40 mph with gusts to 60 mph in the evening decreasing to 15 to 25 mph with gusts to 40 mph. North 15 to 30 mph. Gusts up to 35 mph increasing to 45 mph in the afternoon.
Expected snowfall: No accumulation. | SWE = none. in. No accumulation. | SWE = none. in. No accumulation. | SWE = none. 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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