Monday, January 11th 2016 6:47 am by Wendy Wagner
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
Today we have a CONSIDERABLE avalanche danger at the Alpine elevations in, and surrounding, Turnagain Pass. Wind slab avalanches 1-2' feet thick will be likely for people to trigger on slopes around 35 degrees and steeper. Cornices are also expected to be touchy today and could trigger an avalanche below. Areas at the Treeline elevations have a MODERATE danger for wind slabs in exposed locations as well as glide avalanche potential.
*If skies clear today for travel above treeline, careful snowpack evaluation and cautious route-finding are recommended. The most likely place to trigger an avalanche will be where winds have loaded, or are actively loading, slopes.
In areas such as Summit Lake, the snowpack is shallower and harbors more weak layers. Click HERE to read Saturday's Summit Lake Summary.
|Show the Complete North American Avalanche Danger Scale|
|Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.|
|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.|
After two warm Pacific storms moved through over the weekend, it seems we will get a break in weather for the next few days. Precipitation and snowfall totals from Friday through this morning are listed below. The numbers are in 'water equivalent'. The rain/snow line has been fluctuating between 1,000' and 2,000' during this three-day stretch.
Friday Saturday Sunday STORM TOTAL
Turnagain Pass 1.1 + 0.4 + 1.4 = 2.9" water equivalent (~20" dense snow)
Girdwood Valley 0.7 + 1.2 + 0.8 = 2.7" water equivalent (~20" dense snow)
Summit Lake 0 + 0.1 + 0.1 = 0.2" water equivalent (~2" dense snow)
Due to very limited visibility yesterday, we do not have information for the Alpine elevations. We can expect however, with dryer snowfall (adding 10-12" yesterday) at these higher elevations and strong winds, natural wind slab avalanches, as well as cornice falls, were occurring. With the possibility for clearing skies today, things to watch for will be wind slab avalanches and cornices. Keep in mind:
- Easterly ridgetop winds are forecast to remain strong enough to transport snow above treeline today (20-30mph)
- Although winds are generally Easterly, they can be channeled by the terrain and load, or cross-load, a variety of aspects
- Watch for, and steer clear of, slopes being actively loaded
- Watch for smooth rounded surfaces and hollow feeling snow, stiff snow over softer snow
- Informal tests, such as sticking your boot (or pole) in the snow to feel if softer snow sits under stiffer snow, can be great ways to assess if there is a wind slab. This should be done on low angle slopes without avalanche potential before venturing onto steeper terrain.
Cornices have grown considerably during the past few weeks. Not only do they have the potential to fall naturally, but also to be triggered by the weight of a person or snowmachine. They can also trigger an avalanche below and, all in all, be VERY dangerous. Travel under or on them should be avoided. And remember, they have the tendency to break farther back from the ridge than expected.
Glide cracks have been appearing throughout Turnagain Pass over the last couple weeks. As you travel through the backcounty this week, pay attention for large open cracks in the snow, 'crevasse looking' features, these can release spontaneously without any warning. Similar to managing cornices, it is best to avoid traveling on or under slopes with glide cracks.
Photo below was sent to us yesterday from Turnagain Pass. These glide cracks are in the Treeline elevation band (between 1,000' and 2,500'). Although the cracks are slightly obscured by yesterday's snowfall, you can still see them looming.
Yesterday's pulse of moisture ended up being a bit more potent than forecast, as mentioned above. Turnagain Pass saw roughly 10-12" of snowfall above 2,500' and rain at the road elevation. Along with the snow and rain, ridgetop winds were strong, blowing in the 30's and 40's mph with gusts over 70mph. Temperatures were warm, 37F at 1,000' with a rain/snow line hovering right around 1,600' (give or take).
Today we should see skies begin to breakup and precipitation to continue to diminish. Ridgetop winds, on the other hand, are forecast to remain moderate to strong from the East - averaging in the 20-30's with stronger gusts. Temperatures will remain warm as well, in the mid 20's F on the ridgetops and near 35F at 1,000'.
Tuesday through Thursday it looks like we should have a break between storms. Temperatures are forecast to cool slightly, skies clear off and winds shift to a Northerly direction. Stay tuned.
PRECIPITATION 24-hour data (6am - 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880')||31||8||1.4||91|
|Summit Lake (1400')||35||1||0.1||27|
|Alyeska Mid (1700')||33||1||0.75||64|
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: May 06, 2018 )
|AREA||STATUS||WEATHER AND RIDING CONDITIONS|
|Johnson Pass:||Closed||Closed as of April 20th|
|Placer River:||Closed||Closed as of April 17th|
|Skookum Drainage:||Closed||Closed as of April 1st.|
|Turnagain Pass:||Closed||Closed as of May 7th. Happy summer, see ya when the snow flies!|
|Twentymile:||Closed||Closed as of April 13th|
|Carter Lake:||Closed||Closed as of 4/27|
|Lost Lake Trail:||Closed||Closed as of April 13th|
|Primrose Trail:||Closed||Closed as of April 13th|
|Resurrection Pass Trail:||Closed||Closed as of April 20th|
|Snug Harbor:||Closed||Closed as of 4/27|
|South Fork Snow River Corridor:||Closed||Closed as of April 13th|
|Summit Lake:||Closed||Closed as of April 20th|
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