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Avalanche Advisory

Turnagain Area Avalanche Advisory
Tuesday, March 19th 2019 7:00 am by Aleph Johnston-Bloom
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 today.  Very large avalanches occurred naturally Sunday and Monday sending debris far into runout zones and through flat areas. Slopes are loaded with 8 to 15 feet of snow. Today is a break between storms. However, natural avalanches are still possible and human triggered avalanches are likely today.  These could be very deep and dangerous and extra caution is advised.  Give cornices a wide berth. Careful snowpack evaluation, cautious route-finding and conservative decision-making are essential. 

PORTAGE VALLEY:  Travel in runout zones from avalanches including venturing along and past the Byron Glacier Trail continues to be not recommended. 

SUMMIT LAKE (& INTERIOR EASTERN KENAI MTS):  Large to very large human triggered avalanches remain likely. Between 2-3 feet of snow has fallen onto a very weak snowpack and avalanches are releasing in old buried weak layers.

SEWARD/LOST LAKE:  Large and dangerous natural avalanches have been observed in this area. Today human triggered avalanches are likely in this region as well.  


 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.
3 Considerable Below Treeline / Below 1,000' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
Special Announcement
  • Turnagain Pass 20 years later: On Saturday, March 23rd from 12-2pm swing by the Turnagain Pass moto lot and meet the CNFAIC avalanche forecasters, bring and test your avalanche rescue gear and learn about the history of Turnagain Pass and the CNFAIC. We'll even have a few beacons buried so you can test your skills before heading into the hills!
  • Feeling sporty? Want to support avalanche education in Alaska? Head to the Alaska Avalanche School Ski-Mo (uphill/downhill) fundraiser race at Arctic Valley on Sunday, March 24th at 1pm. For more information click HERE. Great fun! Great cause!

Avalanche Problem 1

Storm Slabs

Almost Certain
Very Likely
Likely
Possible
Unlikely

Chance

Historic
Very Large
Large
Small

Size

Yesterday the large natural avalanches kept occurring with notable avalanches observed in Crow Creek, on Tincan, Seattle Ridge, Petes North, Twin Peaks, and through Summit Lake. These had very deep crowns, and were running into the flats in many locations. This was the second day in a row of very large slab avalanches. Today is a break in the barrage of storms after 6 days of HIGH avalanche danger. Temperatures are dropping this morning but are expected to rise again this afternoon and it should be partly sunny today. The natural avalanche activity should decrease but the potential for a very large human triggered slab avalanche remains. The current snowpack needs some time to adjust to all the loading from multiple feet of snow, strong winds and rain. Be patient! We are optimistic that at some point it will stabilize but today is definitely not the day test it out.  Choose terrain very wisely. The slabs could be very deep, there may be no signs of instability and it could be the 1st or the 10th skier or snowmachine on the slope that triggers the avalanche.  Avalanches could be triggered remotely from thin spots. In addition, pay attention to solar warming and the potential for roller balls and wet loose avalanches on sunny aspects. 

Tincan avalanche. Occurred sometime between 12:15-12:25 pm. 3-18-19. Photo: Corey Anderson

 Avalanche to the ground on Seattle Ridge, 3-18-19. 

Large avalanches, Templeton - Summit Lake, 3-18-19. 

 


Additional Concern

Cornice

Stay away from cornices. They have grown large and could be very tender and dangerous today. Triggering a cornice fall also has the potential to trigger a deep avalanche on the slope below. 


Mountain Weather

Yesterday: Mostly cloudy skies and rain/snow showers on and off throughout the day favoring Portage and Girdwood. Temperatures were in the 30Fs and 40Fs. Winds were northeasterly 15-25 mph with gusts into the 50s. Overnight skies became broken and temperatures dropped slightly. Easterly winds decreased blowing in the teens with gusts into the 30s. 

Today: Partly sunny skies with temperatures in the 20Fs to high 30Fs. Sea level temperatures will be around 40F. Winds will be easterly 5-15 mph with gusts into the 20s. Clouds move back in tonight and winds pick up early morning Wednesday as the next warm wet storm moves over the region. Snow should start overnight. 

Tomorrow: Mostly cloudy with rain and snow showers that could be heavy at times. Rain/snowline is forecasted around 2000'. Easterly winds blowing 20-30 mph gusting into the 50s. The warm wet pattern is forecast to continue into the weekend. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 35   0   0.1    88 
Summit Lake (1400') 37  0.1   30
Alyeska Mid (1700') 34  0.46    78 

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  25   NE  20   62
Seattle Ridge(2400') 30  *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, 2019 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: ClosedClosed as of 4.3.19
Placer River: ClosedClosed as of 3.20.19 due to lack of snow.
Skookum Drainage: ClosedPlacer access closed as of 3.20.19 due to lack of snow.
Turnagain Pass: ClosedClosed as of 5/6. Thanks for a great season all, see you next winter!
Twentymile: ClosedClosed as of 3.20.19 due to lack of snow.
Seward District
Carter Lake: Closed
Lost Lake Trail: ClosedClosed as of 3.22.19 due to lack of snow
Primrose Trail: ClosedClosed as of 4.3.19 due to lack of snow
Resurrection Pass Trail: ClosedClosed for the 2018/19 season. Next season will be open to motorized use.
Snug Harbor: ClosedClose as of 5.1.2019
South Fork Snow River Corridor: ClosedClosed as of 3.20.19 due to lack of snow.
Summit Lake: Closed

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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
© 2019 Chugach National Forest Avalanche Information Center. All rights reserved.
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