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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Saturday, November 26th 2016
Created: Nov 26th 4:13 am
2 Moderate Alpine / Above 2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Treeline / 1,000'-2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
0 NO RATING Below Treeline / Below 1,000'
 Show the Complete North American Avalanche Danger Scale
Bear Tooth Theatre Pub & Grill
Special Announcement

Motorized use on Turnagain Pass is closed due to insufficient snow cover.  Please see riding area status at the bottom of this page for the most up-to-date information.

Snowmachine Specific – Avalanche Awareness and Rescue at AMDS
November 30 @ 6:30 pm - 8:00 pm | FREE
Join CNFAIC forecasters at Alaska Mining and Diving Supply for a discussion on Avalanche Awareness and Rescue. Topics addressed will be:

  • Recognizing safe zones vs. avalanche terrain, not always as simple as it sounds…
  • Situational awareness – clues to watch for to help determine an unstable snowpack
  • Rescue – what’s new with rescue gear (i.e., airbags) and what really saves lives
  • Backcountry responsibility – it’s not just our group out there

We hope to see you and your riding buddies Wednesday, Nov 30th from 6:30 till 8:00pm!!!


The Bottom Line

The avalanche danger is MODERATE in both the alpine and at treeline on all aspects due to a widespread layer of buried surface hoar. Human triggered slab avalanches 10-20” thick are possible. Be extra aware of changing weather conditions and any additional stress being added to the snowpack today. If the forecasted wind and snow start early expect the hazard to bump back up to CONSIDERABLE. Caution and safe travel protocol is advised if venturing in the backcountry. Avoid travel underneath glide cracks. 

***Observations from the Summit Lake area on the Kenai are showing a similar snowpack. Weekly summaries will begin on December 2nd.

 


Primary Concern

Yesterday was the second day since the surface hoar was buried on November 17th that we haven’t received any reports of human triggered slab avalanches in Turnagain Pass. With time this layer of buried surface hoar is becoming more stubborn and less reactive but this also means the slab has the potential to fracture once well onto the slope. This layer hasn't gone away and still needs to be a major factor in slope choice. Remember buried surface hoar is persistent weak layer and human triggered avalanches are still possible. Observations around Turnagain pass continue to show that this layer is widespread throughout the terrain. Dozens of human triggered and remote triggered avalanches have occurred since November 17th on the popular slopes of Tincan, Sunburst, and Magnum. These avalanches have been small to medium in size; just large enough to bury a person or seriously injure you in a ride. Larger and/or steeper, more wind-loaded slopes that haven't been ridden still have potential to avalanche and could have high consequences because of this weak layer. This is important to keep in mind today and throughout the weekend with more snow heading our way. Today new snow and wind increasing late in the afternoon may cause the danger level to rise. Pay attention to changing conditions, additional load will only make the consequences even larger. Be on the lookout for obvious signs of instability like blowing snow, shooting cracks and whumphing sounds.  In addition new snow and wind will be loading weak surface snow (new layer of surface hoar and near surface facets) that has developed over the past few cold clear days and may be reactive at this interface as well.

With the holiday weekend there could be more people heading into the backcountry. Be extra aware of other groups above and below you and only expose one person on a slope at a time.

National Avalanche Center Danger Scale tutorial: HERE.

Buried surface hoar found easily in a snow pit on Tincan yesterday at 2700'. Photo: Andy Moderow  


Secondary Concern

There were two glide avalanches reported on November 23rd and other glide cracks have been observed around Turnagain and Summit area. If you see a glide crack give these a wide berth, minimize time spent underneath, and remember these are totally unpredictable. They are not triggered by humans and are the entire snowpack releasing. These will also be hard to see when covered up by new snow and wind loading. 

 

Glide crack opening on the face of Common Bowl on Tincan. Photo: Andy Moderow

 


Mountain Weather

...WINTER WEATHER ADVISORY FOR BLOWING SNOW REMAINS IN EFFECT
FROM 5 PM THIS AFTERNOON TO 5 AM AKST SUNDAY THROUGH TURNAGAIN
PASS AND PORTAGE VALLEY... See link HERE for more details.

Yesterday started with light snow in the morning with a inch of accumulation. Skies cleared in the afternoon and valley fog moved in late in the day. Temperatures were in the low 20Fs. Winds blew easterly in the 20s in the morning and shifted to northerly and light in the afternoon. Overnight the temperatures dipped into the teens and the winds were light.

Today will be partly to mostly cloudy as the storm approaches. Snow is expected to start this afternoon and winds are forecasted to pick up gusting into the 30s from the SE. 0-3" of snow is possible. Temperatures should rise to the high 20Fs. Tonight the snowfall and wind will continue with 5-10 inches forecasted to fall and gusts into the 40s. Temperatures should remain in the 20s. 

Tomorrow temperatures should dip back down to low 20Fs. Winds should become light and northerly and there is still a chance of light snow. There is a bit of clearing trend into the middle of the week and then more snow on tap for the weekend. 

PRECIPITATION 24-hour data (6am - 6am)

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 19  .1   18
Summit Lake (1400') 21  1 .1  3
Alyeska Mid (1700') 20 0 0  3

 

RIDGETOP 24-hour data (6am - 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  n/a n/a  n/a  n/a 
Seattle Ridge(2400')  16 variable  15   30

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).

Winter snowmachine use open/closed status and riding conditions updates

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: May 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
Summit Lake: Closed

Subscribe to the Turnagain Area Avalanche Advisory:

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur. This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.


USFS SNOW AND AVALANCHE HOTLINE (907) 754-2369
If you have comments or questions regarding CNFAIC operations or winter recreation management, please email staff@chugachavalanche.org
© 2017 Chugach National Forest Avalanche Information Center. All rights reserved.
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