Avalanche Advisory: Friday - Jan 3, 2020

THIS AVALANCHE ADVISORY EXPIRED ON January 4, 2020 @ 6:54 am
Avalanche Advisory published on January 3, 2020 @ 6:54 am
Issued by Steve Mace - ESAC

MODERATE avalanche danger exists at upper elevations today due to the risk of lingering wind slabs on easterly and southerly aspects.  While LOW avalanche danger resides at mid and lower elevations it will not be impossible to find isolated areas of unstable snow.

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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Despite the high winds recorded in the alpine yesterday, field observations did not report much snow transport.  Strong northerly winds have largely stripped the high-country of loose snow over the last week.  While it will be unlikely to find fresh wind slab development today, it may be possible to find isolated areas where lingering wind slabs are sensitive to human triggers, particularly on easterly and southerly aspects at upper elevations. Be suspect of terrain features that encourage drifting such as the leeward sides of ridgelines, gully features, and cross-loaded depressions. Elevated caution is recommended in extreme terrain and on unsupported slopes where the consequences of an avalanche are elevated. Use surface clues to identify wind loaded areas and do your own localized assessments before committing to suspect terrain.

Avalanche Problem 2: Loose Wet
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Cool temperatures allowed for a hard freeze overnight, however, highs are expected near 50°F at lower elevations today. While mostly cloudy skies will limit the solar input, cloud cover may also lead to a greenhouse effect. Be on the lookout for warming surface snow at lower elevations. Solar aspects will be most concerning particularly if the cloud cover breaks allowing for the sun to shine through. Wet, sticky snow surface, rollerballs, and pinwheels are all signs of surface warming and may foreshadow larger point release avalanches.

advisory discussion

While our recent high pressure has been favorable for the avalanche conditions strong winds continue to drive change here in the Sierra.  The sheer size of our forecast area and the variability that exists from one end to the other can lead to drastically different conditions. While the distribution and sensitivity of wind slabs are decreasing it will not be impossible to find areas where consequential wind slabs remain a hazard.  In addition, variable surface conditions and low snow coverage are making for difficult access and treacherous conditions in many areas. Enjoy the pleasant weather today and remember it’s a long season ahead.

recent observations
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1/2 - Mammoth Area - Snow conditions in the Sherwins

1/2 - Mammoth Area - Conditions on Duck Pass

1/2 - Mammoth Area - Snow conditions on San Joaquin ridge

1/1 - Mammoth Area  - Duck Pass, Pika Peak

1/1- June Lake - Strong winds, reactive wind slabs

1/1 - Mammpth Area - Wind Transport along the Mammoth crest, Loose wet activity

Weather and CURRENT CONDITIONS
weather summary

 We can expect the dry and mild conditions will continue today with warm temperatures and light to moderate southwest winds.  High-level clouds will remain throughout the day today and may lead to a green housing effect. 

Sunny skies will return tomorrow with continued warm temperatures and increasing winds. 

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. Mostly cloudy then becoming partly cloudy. Sunny.
Temperatures: 42 to 47. deg. F. 23 to 28. deg. F. 38 to 44. deg. F.
Mid Slope Winds: Light winds becoming southwest around 15 mph with gusts to 35 mph in the afternoon. Southwest 15 to 30 mph. Gusts up to 45 mph increasing to 55 mph after midnight. Southwest 15 to 30 mph. Gusts up to 55 mph decreasing to 45 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. Partly cloudy Sunny.
Temperatures: 37 to 42. deg. F. 19 to 24. deg. F. 32 to 37. deg. F.
Ridge Top Winds: Light winds becoming southwest 15 to 25 mph with gusts to 40 mph in the afternoon. Southwest 25 to 35 mph increasing to 35 to 55 mph after midnight. Gusts up to 70 mph. Southwest 35 to 50 mph decreasing to 25 to 40 mph in the afternoon. Gusts up to 65 mph.
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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