Wednesday, January 6th 2016 7:00 am by Aleph Johnston-Bloom
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
Today the danger at Treeline and above Treeline is MODERATE. The likelihood of triggering a Wind Slab avalanche 2-4’ deep is possible above 1000’. These slabs are most likely to be triggered on steep leeward slopes. Large fresh cornices loom above much of this same terrain and should be avoided. For the periphery of the core Turnagain advisory zone (Girdwood Valley and south towards Summit Lake) where the overall snowpack is thinner elevated caution is advised. There are still buried weak layers that have been reactive and could produce a Deep Slab avalanche.
Human triggered avalanches are possible today. Don't let the sunshine effect decision-making. Identify steep terrain and areas of concern, evaluate the snowpack carefully, watch for signs of instability and practice safe travel techniques.
Below 1000' the danger is LOW.
|Show the Complete North American Avalanche Danger Scale|
|Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.|
|Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.|
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Mark your calendars for two CNFAIC events this week!!
- Thursday night: Our final Fireside Chat, topic snowpack and weather, will be in Anchorage at the Alaska Avalanche School at 6:30pm.
- Saturday day: Hands-on Avalanche Rescue Workshop - 11:00-12:30 at the motorized lot on Turnagain Pass.
All events are free to the public! You can see other upcoming events and courses on our Calendar tab above.
With sustained winds averaging in the mid-50’s mph on Sunday (and gusts to 101mph on Sunburst) 2-4' thick wind slabs are possible on steep leeward slopes, particularly above treeline; though it is worth recognizing that strong winds such as these have a tendency to load slopes far below ridgelines, creating a mid-slope avalanche problem. There was significant cross-loading as well. Identifiying where the winds deposited the snow is crucial. Look for pillowed snow, listen for hollow sounds and pay attention to stiff snow under your skis, snowboards or snowmachines. Watch for shooting cracks and remember even a small pocket of wind slab in steep terrain can have high consequences. Wind slabs are notorious for letting you travel out onto them and then breaking above you. Evalute carefully before commiting to steep terrain from above or below.
Sustained winds, relatively warm temps and moist snow have continued to grow large cornices. These have the potential to fall naturally or be triggered by the weight of a person or machine and can be very dangerous. Travel under or on them should be avoided. They have the tendency to break farther back from the ridge than expected and can trigger an avalanche on the slope below by adding a lot of weight quickly. As you approach ridgelines and the entrances to backcountry bowls make sure you aren't accidently traveling on overhanging snow.
In some parts of the advisory area now sitting under 5-7' of settled storm snow is a layer of old faceted snow on top of the Thanksgiving Rain Crust. This still needs to be a consideration as you travel into the backcountry today. This is a low probability, very high consequence set-up. It is important to use safe travel practices and do not overload slopes with multiple skiers, boarders or snowmachines. Limiting your exposure time spent underneath large paths such as those that effect areas like Johnson Pass and the Lynx Creek drainage. In addition we have limited snowpack information from Johnson Pass and Lynx Creek but we know that the snowpack is shallower. The surface hoar that developed prior to Christmas may be buried and preserved especially near the creek. Watch for signs of instability: recent avalanches, shooting cracks, collapsing and whumpfing. Pay attention to snow depth and trigger points. Deep slabs are most easily triggered from shallow spots where the weight of the traveler can more easily effect the weak layer.
NOTE: In areas such as Summit Lake, the snowpack is shallower and harbors more weak layers under the recent storm snow. See Wendy’s observation and write-up from a snowboarder-triggered avalanche (Saturday) that failed on a buried surface hoar layer that ran on a mellow (28-30 degree) slope.
The stormy weather moved out yesterday, skies cleared and winds died down. The winds were Easterly in the morning 15-25 mph, gusting in the 50's and then shifted to the west and have been light overnight. Temperatures were in the mid 20Fs at ridgeline and 30Fs at 1000'. There was a cooling trend overnight.
Today will be mostly clear and sunny as we have a break inbetween storms. Temperatures will be in the mid 20Fs to mid 30Fs. Winds will be light and Westerly. The clouds will build again this evening and there is chance of snow showers overnight and tomorrow. The next Low is forecasted to move into the Gulf and effect the forecast area into the weekend.
PRECIPITATION 24-hour data (6am - 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880')||30||0||0||85|
|Summit Lake (1400')||27||0||0||27|
|Alyeska Mid (1700')||32||0||0||32|
RIDGETOP 24-hour data (6am - 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
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).
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 15, 2019 )
|AREA||STATUS||WEATHER AND RIDING CONDITIONS|
|Johnson Pass:||Closed||Closed as of 4.3.19|
|Placer River:||Closed||Closed as of 3.20.19 due to lack of snow.|
|Skookum Drainage:||Closed||Placer access closed as of 3.20.19 due to lack of snow.|
|Twentymile:||Closed||Closed as of 3.20.19 due to lack of snow.|
|Lost Lake Trail:||Closed||Closed as of 3.22.19 due to lack of snow|
|Primrose Trail:||Closed||Closed as of 4.3.19 due to lack of snow|
|Resurrection Pass Trail:||Closed||Closed for the 2018/19 season. Next season will be open to motorized use.|
|Snug Harbor:||Open||Rainbow Lake was still frozen with small patches of melting ice as of Sunday afternoon Apr 14th. Snow is melting fast along the first 1/2 mile of road from trailhead.|
|South Fork Snow River Corridor:||Closed||Closed as of 3.20.19 due to lack of snow.|
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