Avalanche Advisory: Friday - Jan 11, 2019

THIS AVALANCHE ADVISORY EXPIRED ON January 12, 2019 @ 6:18 am
Avalanche Advisory published on January 11, 2019 @ 6:18 am
Issued by Steve Mace - ESAC

Moderate Avalanche danger will exist today near and above tree line.  While wind slabs will be harder to trigger today, It will be possible to find sensitive wind slabs on W-NW-N-NE-E slopes in areas with topography that encourages drifting.  

With another warm day today Loose wet avalanches will be possible on solar 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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The primary concern today will be wind slabs on northerly aspects at mid and upper elevations. Winds have generally been light over the last 24hr and remained out of the south.  Fresh slab development is unlikely and existing slabs are starting to stabilize. However it will still be possible to find specific areas that are sensitive to human trigger. Use surface clues to identify and avoid wind-loaded slopes over 35°. Fresh cornice growth, drifting, and uneven snow surfaces are all signs that wind slabs are in nearby terrain.  Size and distribution of wind slab is likely greater in alpine terrain. With another warm day ahead be cautious on wind loaded solar aspects where wind slabs may become more sensitive.

Avalanche Problem 2: Loose Wet
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With another warm day expected today loose wet avalanches wll be possible on southern aspects. Likelihood will increase today if the clouds break and slopes recieve more solar radiation.  Be on the look out for signs of warming including wet snow surface and rollerball activity.  Resulting avalanches are likely to be small but large enough to take a skier off their feet. Be particularly cautious in steep exposed terrain where the consequence of a fall is higher.

Avalanche Problem 3: Persistent Slab
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While the Structure of the snow pack remains poor, recent observations are suggesting a healing trend. Triggering a persistent slab avalanche will be unlikely today though the possibility is certainly still there and a resulting avalanche would likely be large and destructive. Careful snow pack evaluation and conservative terrain choices that limit your exposure are recommended today. 

advisory discussion

The 8-10” of new snow from Wednesday's storm appears to have bonded well and the underling snow seems to be settling in. Travel yesterday was much more pleasant than the upside-down snow of a few days ago.  Our focus today remains on sensitive wind slabs near and above tree line. We haven’t seen much evidence of persistent sab avalanches, however the weak structure and persistent grain types remain concerning. While many signs point towards a decreasing likelihood, significant collapsing was noted on a treed slope in the convict drainage yesterday suggesting that this layer still has energy in areas.  Persistent problems like this can challenge our patience and act in surprising ways.  Evaluate your options carefully and when in doubt, stick to lower angle, less consequential terrain. 

recent observations
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1/10 Natural activity and collapsing in Convict creek

1/10 Mini Morison Obs

1/09 Virginia Lakes Obs

1/09 Chicken Wing

Weather and CURRENT CONDITIONS
weather summary

For today expect to see Warm temperatures and mostly cloudy skies.  Daytime highs will reach into the mid 30’s today at upper elevations and ridge top winds will be mostly light and out of the south. 

There is a slight chance of showers tomorrow as the next active system begins to materialize. Temperatures are expected to drop below freezing tomorrow with continued light south winds.

Our next weather system looks to be arriving Monday evening and we should see significant showers throughout the week.

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. Mostly cloudy. Slight chance of Snow showers.
Temperatures: 35 to 41. deg. F. 18 to 23. deg. F. 29 to 34. deg. F.
Mid Slope Winds: South 10 to 15 mph with gusts to 25 mph. Southeast 10 to 15 mph with gusts to 25 mph. Light winds.
Expected snowfall: None in. None in. None in.
Over 10,000 ft.
Friday Friday Night Saturday
Weather: Mostly cloudy. Mostly cloudy. Mostly cloudy. Chance of Snow shower
Temperatures: 28 to 34. deg. F. 12 to 17. deg. F. 24 to 29. deg. F.
Ridge Top Winds: South 15 to 20 mph with gusts to 35 mph. Southeast 15 to 25 mph with gusts to 35 mph. East 10 to 15 mph with gusts to 25 mph.
Expected snowfall: None in. None in. None 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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