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Avalanche Advisory

Turnagain Area Avalanche Advisory
Sunday, April 17th 2016 5:00 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

CONSIDERABLE avalanche danger remains on all slopes under 2,500' in elevation due to an active glide avalanche cycle. Destructive glide avalanches are occurring daily across the region. Avoid being under the runout of glide cracks. In addition to glide avalanches, natural wet loose avalanches are possible and human triggered likely in steep terrain that harbors wet and saturated snow.

In the Alpine the avalanche danger is generally LOW. Watching for lingering wind slabs, cornice falls and human triggered wet loose avalanches. 

***Travel is not recommended in avalanche terrain on the West (motorized side of Turnagain Pass).

 

AVALANCHE OUTLOOK for Monday, April 18th: 

Monday looks to be very similar to today. In general all the avalanche instabilities that have been mostly confined to the 1000'-2500' elevation band may slowly creep into the Alpine as the temperatures remain warm and the sun shines during the day. Pay attention to changing conditions. The hazard may increase to MODERATE in the Alpine.


 Show the Complete North American Avalanche Danger Scale
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
3 Considerable Treeline / 1,000'-2,500' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
0 NO RATING Below Treeline / Below 1,000'
Special Announcement
  • We now will be issuing advisories 5 days a week until our final advisory on Saturday, April 30th.  Advisories will be posted at 7 am each day except Mondays and Wednesdays.
  • We are finished publishing weekly summaries for the Summit Lake zone. Please see the final Summit Lake Summary and springtime tips on this link. Reminder: as the season winds down, we will continue to publish all reports/observations sent in to us!

Avalanche Problem 1

Yesterday at least one new glide avalanche was observed. What was most notable was that new cracks continue to appear and grow. The West facing terrain on Cornbiscuit now is littered with small, progressing cracks that make it essentially un-skinnable. Magnum West face and South face both have growing cracks and even Sunburst's "mini" glide crack is getting more pronounced. This all indicates snow on the move. Pick your route carefully in the 1000'-2500' elevation band.

This current wet snowpack, combined with mostly sunny skies and temperatures above freezing, has us continuing to think glide activity is likely. Our message remains the same: AVOID being under glide cracks and respective runout zonesTo be in the wrong place at the wrong time when a glide releases could likely be deadly. Considering the motorized up-track is threatened by cracks, we are recommending that people do not travel on the up-track or in runout areas along Seattle Ridge.

Cornbiscuit  glide cracks. 4/16

 


Avalanche Problem 2

Wet loose avalanches have been occurring for the past few days. These have been naturally occurring with warm temperatures, rain and direct sunlight affecting surface snow and mostly confined to the 1000'-2500' elevation band. Expect more of the same today and potentially an increase with clearing skies. The few inches of new snow that fell over the past few days above 2000' is primed if heated enough and lower elevation snow is completely saturated. Human triggering a wet loose avalanche in steep terrain is likely. Pay attention to ski penetration and punchy snow as well as roller balls both natural and travel initiated. Remember wet loose avalanches can be hard to escape once initiated and particularly hazardous if they push you into a terrain trap. Take into account what terrain is above you and what you may have to cross under to get back to your car when venturing to cooler snow in the Alpine.

Wet loose activity on Seattle Ridge with glide cracks and old glide avalanches. 

 


Additional Concern

At elevations above 2,500' and in the Alpine the snowpack is generally stable. There are a few things to watch for if traveling in the upper elevations:

- Lingering wind slabs that could be triggered in steep, unsupported terrain. 

- Cornice falls (we have yet to see cornices start falling in the Alpine but this could happen any day with the warm temperatures and direct sunlight).

- Wet loose avalanches on steep solar aspects, both natural and human triggered. These have been predominantly confined to the 1000'-2500' elevation band but this may change and be higher with heating throughout the next two days.

 


Mountain Weather

Yesterday was mostly cloudy in the morning with isolated rain and snow showers trending to partly cloudy by mid afternoon. Temperatures were in the upper 20Fs to upper 30Fs. Winds were light and easterly.

Today and tomorrow are forecasted to be mostly to partly sunny with temperatures in the high 30Fs at 3000' and the high 40Fs at 1000'. Winds will be light and variable. Scattered showers will be a possibility Monday afternoon with increasing clouds and precipitation on tap for Tuesday. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880')  36  0 110 
Summit Lake (1400')  37  0 27 
Alyeska Mid (1700')  35  0 .1   95

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812') 30   ENE 10  20 
Seattle Ridge(2400') 29  SE  15  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: 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
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