CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Monday, February 8th 2016
Created: Feb 8th 6:00 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
Special Announcement

The Chugach National Forest Avalanche Information Center and Friends of the Chugach Avalanche Information Center are pleased to announce the launch of an observations program partnership with Hatcher Pass Avalanche Center.

By clicking the “Observations” link on both hatcherpassavalanche.org and www.cnfaic.org, users can now browse and submit Hatcher Pass observations. Data is mirrored on both sites giving Southcentral Alaska backcountry enthusiasts the ability to quickly browse recent snowpack and avalanche observations throughout the region. Please submit your own observations and spread the word to others! 

Save the dates! Hatcher Pass Avalanche Center and Friends of the CNFAIC are also joining forces to support FREE avalanche education at Hatcher Pass and in Palmer. There will be a FREE companion rescue workshop on Saturday, February 13th, 10:30am-12:30pm, Hatcher Pass Gold Mint Lot and a FREE avalanche awareness class Wednesday, February 17th, 6:30-8pm, Palmer High School Library. Click HERE for more info!


The Bottom Line

There is a MODERATE avalanche danger at the upper elevations around Turnagain Pass for fresh wind slab avalanches. Slab avalanches up to a foot thick will be possible to trigger on slopes that have been, or are being actively, loaded by winds. At the mid-elevations, watch out for glide cracks and stay out from under them; two cracks have released in the past 36-hours. Lastly, give cornices a wide birth; these are large, looming and still breaking off.

*The avalanche danger in Girdwood Valley and Portage Valley may rise to CONSIDERABLE today due to increased precipitation (up to a foot of new snow is possible by this evening). 


Primary Concern

After a short break between storms over the weekend, we have another small system over us today that is a bit more 'blow than snow'. So far only a couple inches of snow has fallen at Turnagain Pass but up to 6" in the Girdwood Valley; we are expecting another 2-5" to fall through the day above 1,000'. Ridgetop winds are the big player today and have increased into the strong category from the East. Add these winds to the new snow, and the existing soft snow available for transport, and we have a wind slab avalanche problem. 

If you are headed out today, watch for areas of wind drifted snow and/or slopes that the winds are actively depositing snow. Traveling over wind drifts on gentle slopes and watching for cracks that shoot out from you is a great way to assess if these wind slabs are not bonding well and could avalanche if the slope is steep enough. Quick hand pits in these areas (stiffer snow over softer snow) are good tools as well. 

CORNICES:
Don't forget, cornices are still falling and the weight of a person and/or snowmachine could help tip the balance. Give these guys a wider berth than you may think necessary along the ridgelines; many have grown to the point where it hard to determine where the ground ends and the cornice begins.

Photo Left: Northeast winds loading Southwest slopes late in the day yesterday, Magnum Ridge. Photo Right: Wind transport over Taylor Pass.
 


Secondary Concern

Two new glide avalanches were seen yesterday in the forecast region. The first was on Pete's South and the second was in Skookum Valley (side note: if you are not familiar with the names at Turnagain Pass check out this map - maps are found under the resource tab!). Avoiding and limiting time under glide cracks is essential as these avalanches will destroy anything in their path. Many many cracks still litter the mid-elevation band at Turnagain Pass and surrounding regions.

Pete's South glide avalanche pictured below, before and after the crack released. Photos Tim Glassett. Additional photos can found HERE.
Left, Glide Crack 1:37pm Sat. 2/6                                                Right, Crack released and avalanched sometime before 11:40am Sun. 2/7
 


Skookum glide avalanche, this slide can easily be seen from the Seward Highway as you pass the Portage Valley road.


Additional Concern

We have been concerned about a layer of weak older snow that sits roughly 2' below the surface. This older snow is essentially last week's surface that became loose and started to facet before it was buried by 2-3' of storm snow Feb 3-5th. Over the weekend, we have found that this old snow/new snow interface has bonded very well - great news. Report from yesterday's investigation HERE. However, we have little to no data for areas South of the Pass, such as the high elevations above the Johnson Pass trail or Summit Lake. Hence, there may be areas that did not bond well and if this is the case large and 'connected' avalanches will be possible. 


Mountain Weather

Partly cloudy skies and light winds covered the region yesterday morning. By the early afternoon, a weak low-pressure system began to move in bringing cloud cover and a bump in Easterly winds (~25mph averages) along the ridgetops. Temperatures remained mild in the 20'sF at the mid-elevations.

Overnight, we have seen an inch of new snow at Turnagain Pass with up to 6" in the Girdwood Valley. The rain/snow line is currently ~500' and may rise to 1,000' by later today. We are expecting an additional 2-5" at the higher elevations by 6pm. Winds will continue in the 20-30mph range from the East along the ridgetops and temperatures are expected to rise to the mid 30's at 1,000' and the mid 20's at 3,500'. 

Tuesday looks to be a short break in weather before a much warmer and wetter system moves in from the South for Wednesday. We could see rain above 2,000' with this next round of storms mid-week.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 28  0.1  109 
Summit Lake (1400') 29  32 
Alyeska Mid (1700') 30   0.5 87 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 22  NE   22 53 
Seattle Ridge(2400') 24 

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.
FCNFAIC