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Avalanche Advisory

Turnagain Area Avalanche Advisory
Saturday, December 2nd 2017 5:53 am by Heather Thamm
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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The Bottom Line

The avalanche danger is CONSIDERABLE in the alpine and at treeline where triggering a slab 1-2+ feet thick will be likely and natural avalanches are possible as stormy weather begins. Remote triggered avalanche are also possible if traveling adjacent to slopes steeper than 35 degrees. Small slopes and large slopes are all suspect and it will be very important to avoid terrain traps and runout zones. Cautious route-finding and conservative decision-making are essential today.  

Below 1000’ the avalanche danger is MODERATE where an avalanche from above is possible.  

*Below Treeline: ICE CLIMBERS in Portage Valley: Avalanches today could release naturally in higher terrain, sending debris over climbing routes. 

For a description of conditions in Summit Lake check out today's summary HERE.

 


 Show the Complete North American Avalanche Danger Scale
3 Considerable Alpine / Above 2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
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.
Special Announcement

 

**Be aware of changing weather and increasing avalanche conditions across Southcentral, Alaska. For Hatcher Pass avalanche conditions see hpavalanche.org.

Motorized use on Turnagain Pass is closed due to insufficient snow cover.  Please see riding area status at the bottom of this page for the most up-to-date information.

Snowmachine Specific – Avalanche Safety and Lessons Learned at AMDS, December 5th @ 6:30 pm - 8:00 pm | FREE Join CNFAIC forecasters at Alaska Mining and Diving Supply for a talk about lessons learned from past avalanche events and get your brain in gear for avalanche season.

The CNFAIC Events Calendar is filling up with avalanche education opportunities. Check it out and find a class that is right for you! 

 


Avalanche Problem 1

The Kenai Mountains continue to have a very touchy early season snowpack. Over the last three days numerous human triggered avalanches have occurred in popular terrain at Tincan and Sunburst. Yesterday three avalanches were triggered remotely at the same time by one skier as they descended the ridge above Common Bowl on Tincan. See photo below. There was also a remote triggered avalanche on Sunburst near the skin track. Luckily we haven’t received word of anyone getting caught or buried. Lets keep it that way! A slab averaging 15” thick is sitting precariously on a weak layer of facets that has proven to be very reactive. Today an additional 2-6" of snow and moderate Easterly winds 20-30mph could increase slab thickness to 2+ feet on leeward aspects. There is a lot of uncertainty as to how much wind and precip will tip the balance for natural avalanches. Either way human triggered avalanches will be likely. Lots of small terrain features in popular areas that don’t normally avalanche have been releasing. This is extremely important to understand because even a small avalanche could have high consequences especially if someone were caught in a terrain trap. Whumpfing, shooting cracks, and recent avalanches are all present and are obvious signs the snowpack is unstable. If you are headed into the mountains, careful snowpack evaluation and conservative terrain choices are required. This early season snowpack is not a good place to push your luck. 

A photo taken above Tincan yesterday of Common Bowl. The three avalanches in this photo were triggered remotely by a skier descending the ridge where you can see two peope in this photo. A big THANK YOU to all who submitted observations yesterday. Check them out HERE.   

 

This photo was taken of the furthest right avalanche from the skin track. Photo by Victoria Lytle


Avalanche Problem 2

Today Easterly winds 20-30mph will be forming fresh wind slabs on leeward features. In the alpine where the new snow/old snow interface is more variable, wind slabs are expected to be forming in places with the poor structure described above.These wind slabs could be touchy and may break into a deeper layer of the snowpack. Either way, today is not the day to be venturing into steep terrain. Bottom line is to avoid all slopes steeper than 35 degrees. 


Mountain Weather

Skies were clear on Friday and temperatures averaged in the 20F’s. Winds were light from the West and no precipitation was recorded. Yesterday evening West winds switched to an Easterly direction as the leading edge of a front entered our region and bumped winds to Moderate (15-25mph). Light snow flurries started falling around 2am and an inch of snow was recorded. 

As a front moves from the Southwest up Cook Inlet today stormy conditions will favor the Susitna Valley, but Turnagain Pass and Girdwood may see 2-6” of snow today.  Easterly winds are expected to be 20-30mph with gusts in the 40’s mph and temperature will also rise throughout the day. Snow is expected to transition to rain near sea level late tonight into Sunday morning. Rain/snow line may reach 2500' by tonight. 

Tomorrow expect heavy precipitation in the upper elevations with rain at sea level as a front moves into the Gulf of Alaska. Strong Easterly winds are expected along along Turnagain Arm and rain/snow line is expected to be around 1500’ tomorrow.  Precipitation and elevated winds are expected through Monday and above freezing temperatures will likely linger into mid week. 


*Center Ridge SNOTEL has a disfunctional temperature sensor and temperatures are not reliable. See Turnagain Pass DOT weather station for current temperates at 1000'.

**Seattle Ridge weather station anenometer is covered with rime is not operating at this time. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') *26  .1  15 
Summit Lake (1400') 16  .2  10 
Alyeska Mid (1700') 25  .11  16 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 20  33 
Seattle Ridge(2400') 26  **n/a  **n/a **n/a 

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 06, 2018 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: ClosedClosed as of April 20th
Placer River: ClosedClosed as of April 17th
Skookum Drainage: ClosedClosed as of April 1st.
Turnagain Pass: ClosedClosed as of May 7th. Happy summer, see ya when the snow flies!
Twentymile: ClosedClosed as of April 13th
Seward District
Carter Lake: ClosedClosed as of 4/27
Lost Lake Trail: ClosedClosed as of April 13th
Primrose Trail: ClosedClosed as of April 13th
Resurrection Pass Trail: ClosedClosed as of April 20th
Snug Harbor: ClosedClosed as of 4/27
South Fork Snow River Corridor: ClosedClosed as of April 13th
Summit Lake: ClosedClosed as of April 20th

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
© 2018 Chugach National Forest Avalanche Information Center. All rights reserved.
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