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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Thursday, February 25th 2016
Created: Feb 25th 6:07 am
4 High Alpine / Above 2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
4 High Treeline / 1,000'-2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
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
Alaska Mountaineering and Hiking
Special Announcement

Mark your calendars for the second annual SNOWBALL this Friday (Feb.26th) at Taproot. This fun-filled, mid-winter fundraiser is a joint effort between the Alaska Avalanche School and the Friends-CNFAIC.  All proceeds directly support avalanche information and education in Alaska!  Iron those Carhartts, break out the sequins, and dust off the top hat…its Snowball time!  Tickets on sale at https://taprootalaska.com/


The Bottom Line

The avalanche danger for Alpine and Treeline (above 1000’) will remain HIGH today due to recent rapid loading, above freezing temperatures and the possibility of sun. Very dangerous avalanche conditions exist as a result of strong winds, 4’ of new snow and a saturated snowpack below 1500’. This set-up is primed for human triggered avalanches. Travel in avalanche terrain is not recommended until the snowpack has had time to adjust. Avoid slopes 30 degrees and steeper, including runout areas in the flats.

The danger is MODERATE below 1,000' where debris from an avalanche above may run.

Dangerous avalanche conditions also exist in the Summit Lake area. See Saturday's Summit Lake Summary and click HERE for recent observations from the last two days.


Primary Concern

An intense two-day storm concluded this morning leaving 4’ of new snow in the alpine. Strong Easterly winds averaged 30-40mph and rain was observed to 1500’ and possibly as high as 2000'. Overnight temperatures remained above freezing at 1000’ and today there is a possibility of clearing skies and sun. This is not a good combination for our currently stressed out snowpack! DON’T FORGET WE HAVE RECEIVED 8” of WATER (over 8’ of new snow) in the last FIVE DAYS and experienced a big avalanche cycle during the first storm event on Sunday, Feb.21. Very little information is known about our most recent loading event, but we did recieve several reports of 'wumpfing' on Tincan and a seperate group could hear avalanche activty in the Johnson Pass area. What we do know is the only thing that will help this snowpack heal is time and cooling temperatures, both of which we do not have.

Today’s weather forecast has us prepared for everything; scattered rain and snow showers, moderate winds, or periods of clearing skies and a posibility of sun. Should the sun grace us with its presence the likelihood of natural activity will increase today. Below is a list of the avalanche problems to be aware of.

Wind Slabs: This morning moderate Easterly winds will continue to add stress to very large wind slabs. These slabs could be as thick as 4-6’ and have the potential to be large, connected and run to the valley floor. If the sun appears today wind slabs will be extra sensitive to a human trigger. Today it is best to avoid all runout zones and stay off of slopes steeper than 30 degrees.

Wet Snow: Today’s weather forecast is calling for scattered rain showers to 2000’, but there is also a possibility of clearing skies and sun. Both weather concerns can produce wet avalanches, but the sun could have a bigger influence on solar aspects, especially in the alpine.

Cornices: Natural cornice fall activity is possible today and will be an additional trigger of large natural avalanches.

Over 8' of snow has fallen in the alpine in Turnigan Pass and many of the steep gullies along Seattle Ridge are full of debris.

 

 

Yesterday afternoon parking was limited due to 12" of wet saturated snow along the road corridor of Turnagain Pass. 

 

 


Secondary Concern

Underneath all the new snow glides are still lurking and have the potential to release at any time. Glides threaten a lot of well-travelled terrain on both the motorized and non-motorized side of the highway. Still looking for a reason to avoid avalanche terrain and runout zones today??? Here is one more avalanche dragon to steer clear of.


Mountain Weather

A potent storm that lasted 2 days has ended this morning depositing 3-4’ of new snow (3.4” of snow water equivalent) in the upper elevations. Yesterday rain was observed to 1500’, but may have reached 2000’ overnight. Temperatures remained above freezing overnight (35F) along Turnagain Pass (1000'). Northeast ridgetop winds were strong for the duration of the storm averaging in the 30-40s mph with gusts in the 70's.

Today a brief break in the weather has us prepared for everything. Snow and rain showers are anticipated with a possibility of 4-6” of snow in the upper elevations. It is also possible that we could experience periods of clearing skies and sun. Moderate Easterly ridgetop winds are expected to become light by early evening. Temperatures will remain warm today with snow/rain line as high as 2000’.

Another storm is on track for Friday with several more stacked up behind it. A continuation of rain, snow, strong winds and warm temperatures is anticipated through the weekend. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 33  6-8" wet snow  1.9  139 
Summit Lake (1400') 34  rain  0.6   44
Alyeska Mid (1700') 33  3" wet snow 1.93  106 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 25   ENE  35 78 
Seattle Ridge(2400') 28 

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: Apr 11, 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: OpenWide swaths of open river in the Placer Valley. Travel with extreme caution!
Skookum Drainage: ClosedSKOOKUM DRAINAGE CLOSED TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: ClosedClosed for the remainder of the 2017 season.
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

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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
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