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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Heather Thamm  
Thursday, January 28th 2016
Created: Jan 28th 6:44 am
4 High Alpine / Above 2,500' Travel Advice: Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.
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.
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The Woodland Family
Special Announcement

State of Alaska Department of Transportation & Public Facilities Avalanche Closure Notification: There will be intermittent traffic delays today on the Seward Highway for avalanche hazard reduction work between Girdwood and Portage near mileposts 89 to 83. Motorists should also expect delays on Portage Glacier Road near mileposts 3 to 5. Delays of up to 45 minutes between 10:00 AM and 3:00 PM should be expected.

 


The Bottom Line

A HIGH avalanche danger exists in the Alpine where a person could trigger a large and destructive avalanche in Turnagain Pass and Girdwood. Today’s elevated danger is based on our travel advice: Travel in Avalanche Terrain is Not Recommended. A CONSIDERABLE avalanche danger is present below 2500’ where the snowpack is wet and saturated and triggering a wet loose avalanche on a steep slope or in a terrain trap will have high consequences. Below treeline a MODERATE danger exists where a wet avalanche from above is possible.

Elevated caution and careful snowpack assessment is recommended for Summit Lake where strong winds and new snow have added stress to a thin snowpack. Click HERE to read the most current Summit Lake Summary and HERE for an observation from yesterday. 


Primary Concern

Yesterday’s stormy conditions caused a variety of avalanche activity at multiple elevations. Several D2’s were seen on Tincan and fresh wet debris was observed in many common slide paths along Turnagain Arm and Portage. In the last 24-hours Turnagain Pass and Girdwood have received over 2’ of new snow in the Alpine, over 2" of rain below 2000' combined with strong NE winds. Today an additional 6-12” of snow is expected in the upper elevations and rain below 2000'.

Expect wind slabs to be large and to have high consequences. Triggering a wind slab 2-5’ thick is likely on steep slopes today where top-loading and cross-loading will be a factor on a variety of aspects. A windslab from above could easily entrain wet snow at the mid elevation band and be quite destructive and impossible to escape. Natural activity is possible today, but with winds backing off this morning, the likelihood of natural activity will be decreasing.

Avoid putting yourself at the bottom of a big runout zone and stay off of steep terrain. Should visibility allow for travel into the alpine, keep your slope angles low and minimize your exposure to steep slopes and terrain traps. Shooting cracks may not be present until its too late.

 

D2 Avalanche on Tincan "CFR" WSW aspect, observerd yesterday around 3pm. This was likely a natural avalanche due to strong winds and increasing temperatures mid day.

 

D2 natural avalanche on the NW shoulder of Tincan, ~2600, as seen from the Seward Hwy yesterday afternoon.

 

 

 


Secondary Concern

Over 2 inches of rain has saturated the snowpack below 2000’. This hazard will be especially dangerous on steep open slopes where an avalanche from above could easily entrain a large amount of wet snow. Today it will be important to avoid steep runout zones, gully features and steep rollovers. Should you get yourself (snowmachiner or skier) stuck at the bottom of a terrain trap, escaping a wet loose avalanche from above will be impossible. 


Additional Concern

Glides continue be in the back of our minds today, especially with the addition of a large amount of rain and snow over the last 24 hours. Several glides have avalanched over the last few days and don’t be surprised if a few more go today. Since glide cracks can spontaneously release at any time, they are best to avoid. Poor visibility today will make it harder to see existing glides, but this is one more reason to steer clear of steep slopes. 


Mountain Weather

From 6am yesterday to 7am today Turnagain Pass received a 2.2” of water, which equals over 2’ of new snow in the Alpine elevation band. Temperatures spiked mid day causing rain to fall as high as 2500’, possibly higher for a few hours. Winds were strong from the NE averaging in the 30-40’s mph most the day with gusts in the 60’s mph.

Today another .5-1” of water is expected to fall, adding another 6-12” of snow in the Alpine. Temperatures will spike again mid day causing rain/snow line to reach as high as 2000’. Winds are expected to decline, 10-20mph from the NE.

Showery conditions will persist tomorrow with our first chance of sun and cooler temperatures this weekend. 



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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 32.5  15  2.2  107 
Summit Lake (1400')  34  0.3 28 
Alyeska Mid (1700') 34  1 2.09  70 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 27  ENE 34  64 
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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