Avalanche Advisory: Saturday - Mar 30, 2019

THIS AVALANCHE ADVISORY EXPIRED ON March 31, 2019 @ 7:00 am
Avalanche Advisory published on March 30, 2019 @ 7:00 am
Issued by Josh Feinberg - Eastern Sierra Avalanche Center

MODERATE avalanche danger exists at upper and mid elevations due to lingering sensitive wind slabs. Just over a day has passed without significant new wind-loading.  Human triggering of wind slabs that formed from 4-16” of new snow and strong SW winds will still be possible, particularly in the northern areas of the forecast zone.  Also be wary of loose-dry sloughing on steep slopes with loose snow, and small loose-wet potential on sunny aspects.  

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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Up to 1.5ft of new snow fell in the northern areas of the forecast zone on Wednesday accompanied by strong SW winds. SW winds persisted through Thursday night continuing to build dangerous wind slabs on leeward slopes especially at mid to upper elevations.  Many skier triggered and some natural avalanches occurred on Thursday, some resulting in very close-calls.  Skier triggering continued yesterday, and some snowpack tests continued to show sensitive propagating results.  Be wary of denser snow on steep slopes particularly on the leeward side of ridges, sidewalls of gullies, and other deposition zones.  While recent slides have been relatively shallow, they could have bad outcomes in consequential terrain.  Do your own localized assessments before committing to steep terrain with potential wind slabs.  If in doubt, give things another day to settle. 

Avalanche Problem 2: Loose Dry
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Clear skies and crisp nights have kept snow surfaces cold.  Where loose snow exists, the upper layers have been faceting, loosing cohesion, and becoming even looser.  Be cautious on steep slopes on non-solar aspects (NE-N-NW) where turns in loose snow could get some sizeable sloughs moving that could sneak up behind you and take you off your feet.  These could be consequential especially if the slope ends in a gully or depression, or trees and cliffs are involved.  Manage your slough wisely or stick to lower angle terrain.  

Avalanche Problem 3: Loose Wet
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Sunny skies and calm to light winds will continue to make small loose-wet slides possible.  Point-releases originating from rock bands will be possible on sunny aspects as they warm.  While small and benign for the most part, these could be more consequential in gully features especially where rocks could be dislodged overhead.  Turns could also trigger loose sloughs on steep slopes at the height of their warming, and could sweep a rider off their feet. 

advisory discussion

Underlying firm surfaces under new snow exist throughout the forecast zone.  This is a contributing factor keeping avalanche activity more concerning.

recent observations
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3/29- June Area - Negatives: Skier triggered avalanche.

3/29 - Convict - Old Man's Bowl: Small skier triggered slide.

3/29 - Convict - Mini Morrison: Areas of sensitive wind slab, small loose wet activity. 

3/29 - Mammoth Crest: Evidence of natural avalanche activity from prior day wind loading and during storm.

3/29 - Mammoth Crest - Crystal Chute: D2 Natural avalanche toward end of wind loading event.   

3/29 - Lundy - Gilcrest:  Snow conditions.

3/28- June Mtn, Skier triggered avalanche, dream mountain

3/28- Lee vining, Recent avalanche activity and continued wind loading on the Dana Plateau

3/28- Mammoth Area, Skier triggered avalanches in the Sherwins

Weather and CURRENT CONDITIONS
weather summary

High pressure through the weekend will keep skies sunny, temperatures mild, and winds light. Expect highs in the mid 30s around 10,000’ today.  

Unsettled weather returns next week, with the potential for a stronger storm at the end of the week

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Saturday Saturday Night Sunday
Weather: Sunny. Clear. Sunny.
Temperatures: 33 to 43. deg. F. 19 to 25. deg. F. 43 to 51. deg. F.
Mid Slope Winds: Light winds. Light winds. Light winds.
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
Saturday Saturday Night Sunday
Weather: Sunny. Clear. Sunny.
Temperatures: 26 to 34. deg. F. 15 to 20. deg. F. 38 to 44. deg. F.
Ridge Top Winds: Light winds. Light winds. Southwest 10 to 15 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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