CNFAIC LogoCNFAIC Logo

Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Sunday, December 22nd 2013
Created: Dec 22nd 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

There is an overall MODERATE avalanche danger today for triggering a slab avalanche 12-16" deep. Natural avalanches are unlikely but human triggered avalanches are possible. Areas of most concern are steep slopes (over 35 degrees) at treeline and above. 

**CONSIDERABLE danger exists in areas with greater snow amounts (over 6" of heavy snow) during the past 24-hours. Suspect areas are Girdwood and Portage Valleys. This means human triggered avalanches are likely on slopes over 35 degrees. 


Primary Concern

We had no reports of avalanche activity yesterday, however the visibility was poor and it looked as though most folks were staying in the trees and out of steep avalanche terrain.

Another small shot of precipitation has added 3-5" of dense snow to our snowpack since Friday night and we have another 1-2" possible for today. The new snow is sticking rather well to the surface but it's the weak snow buried 12-16" down that we are worried about. This new snow is not likely to be enough to overwhelm the buried weak layers but the added weight of a person could be. In fact, we know a person can overwhelm these weak layers by the widespread collapsing that continues at all aspects and elevations in the mountains. For a closer look at our weak foundation click this link and check out the video and see this report from the north side of the Pass.

For today, sticking to lower angle terrain, without steeper slopes above you, will be your best bet at avoiding a potential avalanche. 


Secondary Concern

Though the snow is heavy and wet at the parking lots on Turnagain Pass, it is dry at the upper elevations and able to be transported by the wind. Winds are forecast to shift and start bumping up from the Northwest by noon today and fresh wind slabs may start forming above treeline. This flow direction is prime for loading the Southeast face of Seattle Ridge - the slopes right above the motorized parking lot. By tonight the Northwest flow may reach over 50mph averages, so keep your eyes peeled in case the wind is ahead of schedule.

*Fresh wind slabs will have the potential to overload the weak snow deeper in the pack and larger and more dangerous avalanches could be triggered. Steer well away from any area with fresh wind deposited snow.


Mountain Weather

Yesterday we had light snowfall which turned to rain at sea level in the afternoon. We picked up around 3" of heavy wet snow above 500'. Rain snow line was around 200'. Temperatures were in the mid 20's at the ridgetop stations and low 30's at sea level. Winds were blowing 10mph with gusts to 30mph from the East during the day and have dropped to ~5mph overnight.

During the past 36 hours precipitation totals: 3-5" of heavy wet snow (.3-.6 water equivalent).

It will start out as another soggy day today but cool down by this afternoon as the warm area of low pressure over us moves off to the East. We might pick up 1-2" of snow as this system exits. Winds should shift to the North by mid-morning and increase to the 15-20mph range. With this we should see the temperature drop to the teens on the ridges and mid 20's at sea level. 

On Monday skies should clear up and temperatures continue to drop back to the single digit range with the North flow. Another system looks to brush by us on Christmas Eve and Christmas.

 

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