Avalanche Advisory: Sunday - Jan 24, 2021

THIS AVALANCHE ADVISORY EXPIRED ON January 25, 2021 @ 6:18 am
Avalanche Advisory published on January 24, 2021 @ 6:18 am
Issued by Steve Mace - ESAC

MODERATE danger exists near and above treeline today while LOW danger will persist below treeline. 2-4” of fresh snow and winds shifting around the compass rose will keep Wind slabs as the primary concern on all aspects near and above treeline today. Expect the Size and distribution of reactive wind slabs to increase as more snow and increasing winds impact the area this afternoon and into the evening. Evaluate snow and terrain carefully if you head into the backcountry today and be wary of the very thin obstacle-ridden conditions.

2. Moderate

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

2. Moderate

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

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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    Certain
    Very Likely
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    Possible
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    Very Large
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2-4” of low-density snow has accumulated across the range over the last 48hrs. This new snow has been accompanied by moderate to strong winds that have shifted around the compass rose. With winds shifting back to the SW today and the presence of more slidable snow prior to this storm, northerly and easterly terrain will pose a greater risk to backcountry travelers. However, it will be possible to find small fresh wind slabs on ALL Aspects near and above treeline.  Expect the size and distribution of wind slabs to increase this afternoon and into the evening hours as another round of snow impacts the forecast area.  Large drifts of new snow, uneven snow surfaces, and recent cornice growth are all clues that indicate nearby wind deposits. Do your own localized assessments and be suspect of terrain features that encourage drifting such as the leeward sides of ridgelines, gully features, and cross-loaded depressions. 

advisory discussion

We have been talking about the hazards posed by the thin coverage and exposed obstacles for almost 2 months now. The truth of the matter is that the small amounts of new snow we have received over the last two days has only made it worse. Just enough snow fell to hide many obstacles and areas of bare ground from view while not providing enough cover to slide over them unscathed. Amplifying this risk posed by the low coverage is the fast and slick nature of the underlying snow. Field observations yesterday confirmed “Dust on Crust” conditions at all elevations. A wide variety of hard slick crusts just below the surface are still very much in play. Don’t be afraid to throw your ski or boot crampons in the pack today and be wary of "slide for life" conditions if you venture into the alpine.

recent observations
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1/23- Mammoth Area- New snow, variable conditions in the lakes basin

1/22- Virginia lakes- Thin coverage and fresh snow in Virginia lakes

1/22- Mt Whitney- Minimal snow coverage

1/21- Mammoth Area- Snow conditions in the Lakes Basin

1/21- Mammoth Area- Snow conditions, Red cone ridge

1/21- Mammoth Area-Snow conditions, Hammil bowl

1/21- Mammoth Area- Thin and variable snow conditions, San Joaquin ridge

Weather and CURRENT CONDITIONS
weather summary

Expect a chilly day today with sunny skies this morning becoming increasingly cloudy this afternoon as another round of snow showers approaches the area. winds will be mostly light out of the west this morning increasing in speed as the next storm approaches.

Snow will move back into the region this evening and we should see several waves of precipitation before the week is over. Models continue to show potential for some impressive accumulation particularly mid-week. It's looking like we may just be in for our first major storm of the winter.

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: Sunny then becoming mostly cloudy. Slight chance of snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 10%. Cloudy. Chance of showers. Snow levels below 7000 feet. Chance of precipitation is 80%. Cloudy. Snow showers in the morning, then snow showers likely in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 80%.
Temperatures: 25 to 33. deg. F. 12 to 18. deg. F. 15 to 23. deg. F.
Mid Slope Winds: Light winds becoming southwest 15 to 20 mph with gusts to 30 mph in the afternoon. Southwest 15 to 25 mph with gusts to 35 mph. Northwest 15 to 20 mph with gusts to 30 mph.
Expected snowfall: No accumulation. | SWE = none. in. 60% probability of 1 to 3 inches. 40% probability of 3 to 5 inches. | SWE = up to 0.15 inch. in. Up to 2 inches. | SWE = up to 0.15 inch. in.
Over 10,000 ft.
Sunday Sunday Night Monday
Weather: Sunny then becoming mostly cloudy. Slight chance of snow showers in the afternoon. Snow levels below 7000 feet. Chance of precipitation is 15%. Cloudy. Snow showers likely in the evening, then snow showers after midnight. Snow levels below 7000 feet. Chance of precipitation is 80%. Cloudy. Snow showers. Snow levels below 7000 feet. Chance of precipitation is 75%.
Temperatures: 15 to 23. deg. F. 5 to 10. deg. F. 8 to 16. deg. F.
Ridge Top Winds: West 15 to 25 mph. Gusts up to 25 mph increasing to 35 mph in the afternoon. Southwest 15 to 25 mph with gusts to 35 mph. Northwest 15 to 20 mph with gusts to 30 mph.
Expected snowfall: No accumulation. | SWE = trace amounts. in. 90% probability of 1 to 3 inches. 10% probability of 3 to 5 inches. | SWE = up to 0.20 inch. in. Up to 2 inches. | SWE = up to 0.15 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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