Avalanche Advisory: Monday - Mar 11, 2019

THIS AVALANCHE ADVISORY EXPIRED ON March 12, 2019 @ 6:54 am
Avalanche Advisory published on March 11, 2019 @ 6:54 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

NE winds increased last night over ridge-tops, and will continue at moderate speeds thru today. MODERATE avalanche danger exists at upper elevations on southerly to westerly facing slopes due to the possibility of triggering a fresh wind slab.   

2. Moderate

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Above Treeline
Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

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.
    Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
Avalanche Problem 1: Wind Slab
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    Very Likely
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    Unlikely
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    Very Large
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    Small

NE winds increased over ridge-tops last night and will continue to transport snow thru today. Forecasted gusts up to 30mph have already been exceeded on Mammoth Mtn with speeds consistently above 50mph. Small fresh sensitive wind slabs are most likely to be found on the leeward side of ridges, sidewalls of gullies, and around other features that promote drifting at upper elevations on southerly and westerly facing terrain.  Sunshine this afternoon could make these fresh slabs more sensitive.  

Strong SW winds at the end of last week redistributed the 1.5-2ft of snow that fell earlier in the week, resulting in reports of multiple natural and skier triggered avalanches. While these older slabs have for the most part stabilized, isolated areas may still exist on more north and east facing slopes where a stubborn wind slab could be triggered.    

Be on the lookout for denser wind-deposited snow and do your own localized assessments before committing to steep terrain.  

advisory discussion

Long-awaited days of sunshine finally arrived over the weekend making us search for that forgotten tube of sunscreen.  While the sun felt good on the face, it created a lot of shallow melt-freeze crusts on solar aspects.  Underlying frozen melt-freeze crusts on more southerly aspects will make for a good bed-surface for a small slide to travel further than expected, not to mention the person caught in that slide. 

recent observations
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-3/10 - Mammoth - Sherwins:  Small pockets of sensitive wind slab.

-3/10 - Lee Vining - V-Bowl: Some high elevation wind transport, ridgeline cornices.

-3/10 - June area - Chicken WIng:  Sun effect on slight solar aspects.

-3/10 - Independence - Onion Valley: Sun crusts, small loose-wet point releases, older storm avalanche activity. 

-3/10 - Mammoth - Panorama Dome: Small surface sloughs, small wet-loose point release.

Weather and CURRENT CONDITIONS
weather summary

Mostly cloudy skies are expected this morning with partly cloudy skies and some sunshine this afternoon, with sight chances of light flurries. NE winds picked up at higher elevations last night and should continue thru the day, gusting into the 30s-40s and higher in some areas.  Cold temperatures continue with highs reaching the mid 20s today around 10,000’.  

Our last chance of light snowfall for awhile will be on Tuesday as a fast moving cold-front moves thru the area with little accumulation expected and strong SW winds.  A long awaited stretch of high pressure will build after that thru next week, with warmer temperatures starting over the weekend.  

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Monday Monday Night Tuesday
Weather: Mostly cloudy then becoming partly cloudy. Slight chance of snow showers in the morning. Chance of precipitation is 10%. Partly cloudy then becoming clear. Sunny then becoming partly cloudy. Chance of snow in the afternoon. Chance of precipitation is 35%.
Temperatures: 26 to 34. deg. F. 11 to 17. deg. F. 30 to 38. deg. F.
Mid Slope Winds: Light winds becoming northeast around 15 mph in the afternoon. Gusts up to 25 mph. Light winds. Southwest 15 to 20 mph. Gusts up to 35 mph increasing to 50 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 80% probability up to 1 inch. | SWE = less than 0.10 inch. in.
Over 10,000 ft.
Monday Monday Night Tuesday
Weather: Mostly cloudy then becoming partly cloudy. Slight chance of snow showers in the afternoon. Chance of precipitation is 10%. Partly cloudy then becoming clear. Sunny then becoming partly cloudy. Chance of snow in the afternoon. Chance of precipitation is 35%.
Temperatures: 19 to 25. deg. F. 7 to 12. deg. F. 23 to 29. deg. F.
Ridge Top Winds: Northeast around 15 mph with gusts to 30 mph. East around 15 mph. Gusts up to 25 mph in the evening. Southwest 15 to 25 mph with gusts to 40 mph increasing to 25 to 35 mph with gusts to 60 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 80% probability up to 1 inch. | SWE = less than 0.10 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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