Avalanche Advisory: Sunday - Jan 5, 2020

THIS AVALANCHE ADVISORY EXPIRED ON January 6, 2020 @ 6:33 am
Avalanche Advisory published on January 5, 2020 @ 6:33 am
Issued by Chris Engelhardt - Eastern Sierra Avalanche Center

LOW avalanche danger exists at all Elevations on all Aspects. Stubborn Wind slab on isolated terrain features in complex terrain should continue to be given consideration.

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

With mountains as big and complex as ours, one cannot discount the possibility of lingering stubborn wind slabs in isolated areas of complex terrain. Be particularly aware of unsupported slopes, convex rolls, or cross loaded terrain where a unique situation may have set up and is waiting for a trigger to release tension or weakness in the snowpack.  The thin and spatially variable snowpack that currently exists has plenty of hard wind affected snow that may be residing on weak or slick sliding surfaces such as temperature crusts, water ice, or smooth granite slab.

advisory discussion

There hasn’t been any significant wind slab avalanche activity reported or observed since Dec 29th; activity has been limited to some small Loose Wet activity on Southeast and Westerly aspects on New Year’s Day. The warm temperatures and solar input have continued to consolidate and anchor in the snowpack and the wind has been doing its customary work blowing out the northerly terrain as well as hammering the sunny aspects with its SW prevailing pattern. We certainly have had a lot of northerly wind these past few weeks which has kept forecasters on their toes with snow loading patterns. Although there has been some consolidation and strengthening of the snowpack in many areas, there also has been a lot of metamorphism and degradation of thin snow coverage. Temperature gradients are exacerbated with thin snow coverage and in the shady aspects in the northern and southern part of the forecast zone much of the snow is becoming looser and less cohesive as moisture is pulled out. The bottom line is that the snowpack is extremely variable both in depth and structure across the forecast zone, so every drainage and mountain should be looked at with a critical eye to what is really going on in your specific area.

At this point, the range is looking a little haggard and thin, but despite, there is still enough coverage to find good riding opportunities throughout. One must just be able to dig a bit deeper to find those soft surfaces.

THANKS to all who have been submitting OBSERVATIONS, they’re invaluable to keeping the knowledge rolling and current!

recent observations
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1/3 – Virginia Lakes & Dunderberg Peak – snow conditions

1/2 – Mammoth Area – Sherwins – Solar warming

Weather and CURRENT CONDITIONS
weather summary

 

Sunday will start out partly cloudy and become sunnier as the day progresses. After the lull Saturday afternoon, strong SW winds will again strafe the higher elevations (30-45mph, gusts of 60mph) and are forecast to orient to a more westerly direction this afternoon and subside in velocity a bit (20-30mph, gusts of 45mph). Temperatures will continue to be above freezing in the lower mountains and hover just around 26-32degF above 10000ft. There is a chance for light snow as weak weather systems move through the area Tuesday through Friday with a stronger storm hopefully impacting the Sierra by next weekend.

 

 

 

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Sunday Sunday Night Monday
Weather: Partly cloudy then becoming sunny. Snow levels below 7000 feet. Chance of precipitation is 0%. Clear. Snow levels below 7000 feet. Chance of precipitation is 0%. Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 32 to 38. deg. F. 11 to 16. deg. F. 36 to 41. deg. F.
Mid Slope Winds: West 15 to 30 mph. Gusts up to 40 mph. West around 15 mph with gusts to 30 mph. Light winds.
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
Sunday Sunday Night Monday
Weather: Partly cloudy then becoming sunny. Snow levels below 7000 feet. Chance of precipitation is 0%. Clear. Snow levels below 7000 feet. Chance of precipitation is 0%. Sunny. Snow levels below 7000 feet. Chance of precipitation is 0%.
Temperatures: 26 to 32. deg. F. 10 to 15. deg. F. 30 to 36. deg. F.
Ridge Top Winds: Southwest 30 to 45 mph with gusts to 60 mph becoming west 20 to 30 mph with gusts to 45 mph in the afternoon. Northwest 15 to 25 mph with gusts to 35 mph. Southwest around 15 mph. Gusts up to 25 mph in the morning.
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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