Avalanche Advisory

Turnagain Area Avalanche Advisory Tuesday, November 26th 2013 5:54 am by Kevin Wright ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.

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The MODERATE danger rating above treeline is going to stay with us due to the persistent nature of our problem.  Natural avalanche activity is unlikely, but skier triggered avalanches are possible on steeper slopes in the higher elevations.  Due to thin snow cover, avalanches have been relatively low volume despite reasonably large propagation width in the last few days.  Slab depth is ranging from 6"-20".  

Below treeline is LOW danger with very thin snow coverage and crust.

The next advisory will be on Thursday, Thanksgiving day.  We do not expect major changes in the forecast for Wednesday.  

Show the Complete North American Avalanche Danger Scale

North American Public Avalanche Danger Scale Avalanche danger is determined by the likelihood, size and distribution of avalanches. Danger Level Travel Advice Likelihood of Avalanches Avalanche Size and Distribution 5 Extreme Avoid all avalanche terrain. Natural and human- triggered avalanches certain. Large to very large avalanches in many areas. 4 High Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Natural avalanches likely; human- triggered avalanches very likely. Large avalanches in many areas; or very large avalanches in specific areas. 3 Considerable Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential. Natural avalanches possible; human- triggered avalanches likely. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. 2 Moderate Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Natural avalanches unlikely; human- triggered avalanches possible. Small avalanches in specific areas; or large avalanches in isolated areas. 1 Low Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human- triggered avalanches unlikely. Small avalanches in isolated areas or extreme terrain. Safe backcountry travel requires training and experience. You control your own risk by choosing where, when and how you travel.

2 Moderate Alpine / Above 2,500'

Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

1 Low Treeline / 1,000'-2,500'

Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

1 Low Below Treeline / Below 1,000'

Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Join Wendy Wagner tonight at 630 at the Girdwood Ranger Station for the first of the Fireside Chat series.  This free lecture will cover the topic - Introduction to avalanches and Terrain and Route Finding.

Avalanche Problem 1

The old surface that we were skiing a week ago is the current weak layer, with the November 21st storm snow failing on those loose faceted grains.  See this observation for a detailed look at the snowpack structure.  Since the storm on Friday we have had 3 decent avalanches reported to us, and keep in mind that few people are skiing south of Anchorage right now.  All of these avalanche events are behaving in a similar nature, breaking on the storm interface from November 21st.  The storm snow is heavier and denser than the underlying layer of weak faceted snow, making this failure easy to identify in snowpit tests.  Reports from a couple days ago were identifying failure on isolation or with very light force.  

The picture below is actually from the Summit Lake area, but shows a similar problem farther south on the Kenai.  See this observation for another picture from that reported avalanche.

We expect this kind of avalanche potential to stay for a little while longer.  Time, warm temperatures, and continued storm cycles will eventually fix the problem.  Until then, caution is warranted when deciding where to go right now.  Also keep in mind that the snowpack is shallow.  Rocks and trees are barely covered, if at all.  

There is no new snow in the last 24 hours.  Temperatures are in the high 20s.  Wind is light.  

The National Weather Service continues to have light snowfall in the forecast.  1-3 inches of snow is possible today as a weak surface low enters Prince William Sound this morning.  

Temperatures will stay near freezing in the mountains and perhaps rising above freezing near sea level.  Wind will stay light and variable, 10-20 mph.

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Apr 22, 2018 )

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