Avalanche Advisory: Thursday - Feb 8, 2018

 
 
 
 
 
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THIS AVALANCHE ADVISORY EXPIRED ON February 9, 2018 @ 6:20 am
Avalanche Advisory published on February 8, 2018 @ 6:20 am
Issued by Clancy Nelson - Eastern Sierra Avalanche Center

The overall avalanche danger is rated LOW today. Clear skies, decreasing winds, and well above average temperatures will again make loose wet avalanches possible as daytime warming occurs on E to S to W facing slopes. Poor coverage on solar aspects will limit the problem to isolated areas that have retained the most snow. Use caution on steep, rocky, E to SE aspects as the snow becomes wet.

1. Low

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Above Treeline
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

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.
    Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
Avalanche Problem 1: Loose Wet
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  • Likelihood ?
    Certain
    Very Likely
    Likely
    Possible
    Unlikely
  • Size ?
    Historic
    Very Large
    Large
    Small

Temperatures are forecast to be about 5 degrees warmer today than yesterday, and a good 15-20 degrees above seasonal averages. Point forecasts throughout the region show warming occurring early in the day. Wet instabilities will be increasingly possible in isolated areas on E to S to W aspects as the sun heats the snow. Limited coverage exists on many southerly slopes. Steep, rocky terrain on E to SE aspects and areas that have retained more snow are more likely to see loose wet avalanches today. Be aware of snow pinwheels rolling down the slope around you. Sinking in to wet snow deeper than your ankle is a sign that the snow is becoming saturated and less stable. Timing is everything. If you can be off of sun-baked slopes before too much thawing occurs you can avoid the problem.

advisory discussion

Temperatures are forecast to be about 5 degrees warmer today than yesterday, and a good 15-20 degrees above seasonal averages. Clear skies and below freezing temperatures overnight have allowed the snowpack a solid re-freeze. But clear skies and generally light winds will allow solar aspects to warm quickly today. It’s still mid-winter on the calendar and so the February sun is relatively low in the sky meaning that north-facing slopes will not receive as much solar radiation as east and south facing aspects. The sun has already depleted much of the snowpack on those slopes which means that loose wet avalanches will have limited terrain and limited snow to move down the hill. East to southeast facing gullies and cirques, especially near rock bands and tree cover will be most likely to have wet instabilities.

Just a ridgeline away, on northeast to northwest facing slopes the snow is still cold and wintry, especially above ~9500’. The layers of weak, sugary snow that we have been monitoring all season can still be found throughout the snowpack and their strength has waxed and waned depending on conditions. The lack of substantial precipitation means that the snow on top of these layers is not heavy enough to overpower their limited strength. If the prevailing weather pattern retrogrades offshore and new storms become possible these layers may become more of an issue.

Until then, coverage remains thin and obstacles abound. Be wary of rocks and logs just below the snow surface. Early in the day, and as slopes re-freeze in the afternoon, hard and fast conditions could turn a simple fall into a dangerous slide. Crampons might be a good idea.

 

Weather and CURRENT CONDITIONS
weather summary

Unseasonably mild conditions will continue through Friday. Highs will be 15-20 degrees above average with mainly light winds.

Two-Day Mountain Weather Forecast Produced in partnership with the Reno NWS
For 8,000 ft. to 10,000 ft.
Thursday Thursday Night Friday
Weather: Sunny. Clear. Sunny.
Temperatures: 52 to 58 deg. F. 25 to 33 deg. F. 51 to 59 deg. F.
Wind Direction: Light winds. Light winds. Light winds becoming W
Wind Speed: Light winds. Light winds. Light becoming 10 to 15 mph with gusts to 25 mph in the afternoon.
Expected snowfall: 0 in. 0 in. 0 in.
Over 10,000 ft.
Thursday Thursday Night Friday
Weather: Sunny. Clear. Sunny.
Temperatures: 45 to 50 deg. F. 26 to 31 deg. F. 44 to 49 deg. F.
Wind Direction: S to SE Light winds. Light winds becoming W
Wind Speed: 10 to 15 mph with gusts to 25 mph in the morning becoming light. Light winds. Light becoming 10 to 15 mph with gusts to 25 mph in the afternoon.
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 Snowpack Summary is provided by the Eastern Sierra Avalanche Center, who is solely responsible for its content.

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