CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Wednesday, April 13th 2016
Created: Apr 13th 4:23 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.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
0 NO RATING Below Treeline / Below 1,000'
 Show the Complete North American Avalanche Danger Scale
Alaska Mountaineering and Hiking
Special Announcement
  • We are very sad to report that there was an avalanche fatality on Monday in the Hoodoo Mountains. This was in the Eastern Alaska Range and near where the Arctic Man events were held. Our thoughts and condolences go out the family and friends of the victim. Link to ADN article HERE. 
  • This is the final week of daily avalanche advisories. Between Monday, April 18th and Saturday, April 30th we will be issuing advisories on weekends and intermittently during the week.
  • The Chugach National Forest has closed some riding areas to motorized use due to snow melting out. Please see the table at the bottom of this page for a complete list. Snug Harbor, Summit Lake and Turnagain Pass (N. of Granite creek) remain open. 

The Bottom Line

Below 2500' the avalanche danger is CONSIDERABLE today due to a continued pattern of warm temperatures and an active glide avalanche cycle. Natural wet loose avalanches in steep terrain are possible and human triggered wet loose avalanches are likely.  Avoid being under the runout of glide cracks and travel on or under cornices.

In the Alpine the avalanche danger is MODERATE. Human triggered wind slabs are possible on steep leeward slopes and cornices are also a concern for this elevation band along ridgelines.

***Travel is not recommended in avalanche terrain on the West (motorized side of Turnagain Pass).

If you are headed to the Summit Lake area don't forget to check Summit Lake Summary


Primary Concern

New glide activity was observed yesterday and continues to be the primary concern due the destructive and unpredictable nature of the releases. Travel underneath existing glide cracks is a total gamble. The zone above and around the popular motorized up-track on Seattle Ridge continues to have our hackles up. This well traveled slope is hanging in the balance (pictured below). Although much of the snowpack has already avalanched along Seattle Ridge, there is still a lot of snow that could release. There was no overnight freeze in the 1000-2500' elevation band and there is the possibility of rain today. These weather factors may increase glide activity.

Due to the dangerous and destructive power of even a small glide avalanche, we are recommending that people do not travel in avalanche terrain (including runout zones) on the motorized side of Turnagain Pass (West Side). Glide avalanche hazard also exists on the non-motorized slide of Turnagain Pass. Travel underneath existing glide cracks is not recommended. In addition, be on the lookout for new glide cracks forming. 

An example of new glide avalanche activity (from the past 24-hours). photo: Tim Glasset 

Looking towards the uptrack and noting the amount of snow that still could slide. 

 


Secondary Concern

Yesterday the temperatures rose above freezing in the Alpine and the sun was shining. The new snow got progressively wetter throughout the day. There was some minor natural roller ball activity and some natural wet loose activity on steep slopes. Low elevations were very punchy and saturated in the afternoon. There was no overnight freeze from 1000'- 2500'. This combined with the possibility of rain will up the likelihood and potential for natural and human triggered wet loose avalanches today. Any periods of sunshine will also be a factor. Remember wet loose avalanches can be hard to escape once initiated and particularly hazardous if they push you into a terrain trap.

Natural wet loose avalanche on Seattle Ridge that occurred in the afternoon yesterday. 

 


Additional Concern

Yesterday it was evident that the wind had redistributed the new snow and there were deeper pockets of snow along leeward ridgelines. We have limited information from the Alpine but traveling to 3200' showed a structure that could be triggered on steep wind loaded slopes. Wind effected storm snow sits on top of a stout melt-freeze crust. Watch for cracking while traveling and recognize that this set-up could be sensitive on unsupported features. 

Cornices: We have been wondering when we will see a natural cornice fall cycle. So far they been "hanging in there" but yesterday we observed two cornice falls and the avalanches that were triggered by them in Portage Valley. These were both in terrain at or below 2500'. This is similar to the corniced ridgeline elevations in the Seattle Creek drainage. Continued warm temperatures may increase the likelihood that these will fail. As always, avoid travel on or under cornices at any elevation and remember that they may break farther back than expected. 


Mountain Weather

Yesterday was mostly sunny with some high clouds. Sky cover trended to overcast by the evening. Winds were light and variable. Temperatures were warm, averaging in the high 40Fs at 1000' and the high 30Fs at 3000'. Center Ridge Snotel hit 50F at 4 pm and Sunburst Wx station saw 34F at 3 pm. 

Today will be partly to mostly cloudy with a chance of rain in the afternoon. The temperatures will remain warm and above freezing above 3000'. Wind will be light and easterly. 

The trend for the week is forecasted to be scattered showers and above average temperatures as the general pattern stays the same. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 41   0 114
Summit Lake (1400')  40 31 
Alyeska Mid (1700')  38  0 99 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 32  variable   33
Seattle Ridge(2400')  34  variable  3 18 

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: Apr 11, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: OpenPlease park on road in and leave the turnaround (near outhouse) open for trailers to turn around.
Placer River: OpenWide swaths of open river in the Placer Valley. Travel with extreme caution!
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: ClosedClosed for the remainder of the 2017 season.
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Primrose Trail: OpenPlease STAY ON existing and hardened trail surface through the lower sections of this route.
Resurrection Pass Trail: ClosedClosed for 2016/17 winter season. This is a non-motorized season. This alternates every other year and will open again during the 2017/18 winter.
Snug Harbor: Open
South Fork Snow River Corridor: Open
Summit Lake: Open

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.
FCNFAIC