Avalanche Advisory: Wednesday - Dec 12, 2018

THIS AVALANCHE ADVISORY EXPIRED ON December 14, 2018 @ 6:56 am
Avalanche Advisory published on December 12, 2018 @ 6:56 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

Wednesday:  Strong 60mph west winds, shifting out of the north in the afternoon, will lead to small new wind slabs sensitive to human triggering at all elevations.  Human triggering will be possible.  

Thursday:  Much lighter winds should not form any new wind slabs.  Avalanche concern will decrease thru the day as previously formed wind slabs have time to stabilize and human triggering will become less possible.  

No Rating


Above Treeline

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Near Treeline

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Below Treeline
Avalanche Problem 1: Wind Slab
  • Type ?
  • Aspect/Elevation ?
  • Likelihood ?
    Very Likely
  • Size ?
    Very Large

Wednesday:  Gusty 60mph winds will shift from out of the west in the morning to out of the north in the afternoon, and will likely create new wind slabs on the leeward side of ridges, sidewalls of gullies and around other features that promote drifting at all elevations.  These are stronger winds than we have seen in the past week, and for the first time are affecting lower elevation areas.  This means that slightly more protected areas at lower elevations where more loose snow is available for transport will become more concerning.  Be on the lookout for denser snow deposits and do your own localized assessments to determine how fresh and sensitive these slabs may be.    

Thursday:  Light SW winds will not be strong enough to re-distribute the minimal amounts of loose snow left from previous day’s winds.  Human triggering of wind slabs will become less possible as wind slabs begin to stabilize thru the day.  Although not too concerning, sunny skies and light winds will allow slopes with sunny aspects to warm and small loose wet slides will be possible.

advisory discussion

In addition to the more obvious concern over fresh wind slab development, there still remains concern over older wind slabs that could be sitting on top of a weak layer of facets, or possibly even in much more limited areas on top of weak surface hoar. These weak layers will make it harder for older wind slabs to stabilize.  Be aware of this possibility, and when you are doing your localized assessments and tests take a closer look to see what is sitting under the wind slabs. 

weather summary

Wednesday: Expect sunny skies, mild temperatures in the mid 30s around 10,000’, and strong gusty winds into the 50mph range at lower elevations, and into the 60mph range at higher elevations.  

Thursday: Expect more of the same, except winds will decrease substantially and be shifted out of the Southwest.

Longterm: Slight chances of snow exist for Friday and Sunday, but accumulation amounts continue to drop and look pretty minimal.  A mild high-pressure ridge is expected for next week bringing clear dry conditions and above average

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 Clear Sunny
Temperatures: 34 to 39 deg. F. 19 to 25 deg. F. 36 to 41 deg. F.
Mid Slope Winds: Northwest
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
Wednesday Wednesday Night Thursday
Weather: Sunny Clear Sunny
Temperatures: 30 to 35 deg. F. 21 to 26 deg. F. 32 to 37 deg. F.
Ridge Top Winds: West becoming north in the afternoon West Southwest
Expected snowfall: 0 in. 0 in. 0 in.
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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