CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, March 3rd 2013
Created: Mar 3rd 6:41 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.
2 Moderate Below Treeline / Below 1,000' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
 Show the Complete North American Avalanche Danger Scale
BP Alaska
The Bottom Line

We have a MODERATE avalanche danger today for wind slab avalanches above treeline and persistent slab avalanches below treeline. An increase in easterly wind is expected to load upper elevation south and west aspects. Areas of most concern will be near ridgelines, rollovers and cross-loaded gullies. Additionally, below 3,000’ in the Placer Valley, 20-Mile, Grandview and Summit Lake regions various weak layers exist 2-6’ below the surface. There is the possibility a person could trigger one of these weak layers that results in a larger and more dangerous avalanche.


Primary Concern

Wind slab avalanches will be our primary concern today as ridgetop winds have increased overnight. These are blowing steady at 15-20mph from the east and should continue through the day. Though the wind did kick up two nights ago creating shallow slabs and wind crusts, there still remains plenty of loose snow on the surface to be blown into new slabs and drifts today. Watching for winds actively loading slopes along with stiff and hollow feeling snow that may crack around you will be your best clues to avoid triggering a wind slab.

Additional Concerns:

Cornices – Cornices have grown steadily the past few storms and though several have fallen many are still looming. Avoiding these from both above and below will be prudent.

Loose snow avalanches – Sluffs should be fairly easy to initiate on steeper slopes sheltered from the wind again today. Scattered wind crusts and southerly aspects that may have a thin sun crust should help to limit sluffs.

Recent avalanche activity:
Yesterday’s sunny Saturday was not missed by many. Several folks were out enjoying the powder with human triggered avalanche activity confined to shallow (4-8") wind slabs and loose snow sluffing. Natural activity came in the form of cornice falls and sun induced point releases on southerly aspects. There was one very large cornice that fell midday yesterday onto the south face of Magnum Ridge (image below). This backcountry bomb did trigger a few slabs on the way down that look to be mainly in the recent 3' of storm snow. Right under the cornice it was scoured to the rocks and may have pulled out a couple pockets of snow breaking near the ground. More footage of this can be found HERE.


Secondary Concern

There exist a few layers of concern buried several feet below the surface that we continue to mention. The first one involves various facet/crust combinations below 3,000’. We have not seen any avalanche activity on these layers in the Turnagain Pass region but they are suspect in the Placer Valley, 20-Mile, Grandview and Summit Lake areas (below 3,000’). The second layer of concern deals with weak snow near the ground in areas with a shallow snow cover. This problem is mainly confined to the mountains of the interior Kenai. Triggering an avalanche that breaks at one of these buried weaknesses is more of an outlier event but could be quite large. Safe travel practices, including limiting exposure time in avalanche paths and runnout zones, is a good way maximize a safe day playing in the backcountry.

 


Mountain Weather

Yesterday’s stellar day of blue skies, light east wind and temps in the upper 20’s has given way to high clouds overnight. These are associated with a low pressure system centered south of the Aleutians that will be skirting us to the south. Light snowfall has begun to fall in a few areas and ridgetop winds have bumped up from the east averaging 15-20mph with gusts to 40mph. Temperatures are holding steady around 20F on the ridgelines and 30F at sea level.

Today we can expect light snowfall to continue but is only expected to add up to an inch or so. Winds are likely to remain moderate from the east – averaging 15-20mph with gusts to 40mph. Temperature should stay in the mid 20’sF on the ridgetops but rise a bit at sea level to the mid 30’s where a spitting rain/snow mix is expected.

Tomorrow this system will continue to the southeast and we should see winds decrease and shift to more of a southwest direction. There is a chance for flurries tomorrow but partly cloudy skies with decent visibility is possible too.

 


Fitz will issue the next advisory tomorrow morning, March 4th.

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: Mar 15, 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: Open
Skookum Drainage: OpenSkookum drainage closes to motorized use on April 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: Open
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