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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Aleph Johnston-Bloom  
Wednesday, January 27th 2016
Created: Jan 27th 4:16 am
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.
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Special Announcement

There have been ten people killed in avalanches in the United States since January 16. Fatalities have occurred in Colorado, Utah, Wyoming, Montana, Washington, and Alaska. This in the largest number of US avalanche fatalities in January since at least 2001. Click here to read an analysis of this by Spencer Logan, an avalanche specialist at the Colorado Avalanche Information Center. More information and preliminary reports on all of these acidents can be found at Avalanche.org. 

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The Bottom Line

As rain, wind and snow impact the Turnagain Pass and surrounding areas today we will have a CONSIDERABLE avalanche danger at all elevations above 1,000'. Human triggered storm and wind slab avalanches will be likely on slopes 35 degrees and steeper. Natural avalanches will be possible. Cautious route finding and conservative decision-making are advised as the storm continues through the day.

Yesterday was an active day for glide avalanches. Avoid traveling in areas where glide cracks threaten from above. 

The avalanche danger is MODERATE below 1000' where debris running into channelized terrain from above is possible.


Primary Concern

After a brief break in the stormy weather yesterday, that gave backcountry travelers an opportunity to get out in the sunshine, we are back in it today with a warm, wet and windy storm rolling through. Overnight there has been .5 of water, roughly 5-8" of snow. Today we are expecting another .5"-1" of precipitation; this equates to rain below approximately 1,500' and 5-10" of snow above. The winds have been blowing 30-40 mph from the ENE with gusts up into the 70s actively loading leeward terrain.

In the Alpine, above 2,500', where dry snow is falling avalanche issues are expected to be confined to what we call 'storm snow instabilities'. This means avalanches will be composed of the new storm snow and are not expected to break into layers deeper in the pack. The question will be how well the new snow bonds to the old snow. The most likely avalanches will be on wind loaded slopes where fresh wind slabs 5-20" thick have formed. These are always the most 'touchy' during formation or just after. Avoid travel on or under steep leeward terrain. Smooth rounded surfaces, hollow feeling snow, stiff snow over soft snow and shooting cracks intiated traveling on foot or machine, are all signs of wind loading and something to steer clear of on steep slopes today. 

In the 1000'-2500' elevation band pay attention rain on snow and to how well the new snow is bonding to the old rain crust/snow surface, expect wind slabs especially in cross loaded areas like Seattle Ridge. The rain/wet snow combination may create the conditions for wet loose avalanches in this elevation band. 

*Cornice falls will again be a concern today with the warm temperatures, new snow and wind loading. These can break naturally at anytime as well as under the weight of a person. They can trigger an avalanche below and be very dangerous. 

Note: The Girdwood Valley recieved about twice as much water (.9") as Turnagain pass Sunday and additional load last night. If venturing into the upper elevations around Girdwood, fresh wind slabs and storm slabs are likely to be thicker.  


Secondary Concern

Several recent glide avalanches were observed yesterday. Glide cracks are continuing to open and grow. These are dangerous and unpredictable. As with cornices, these are best dealt with through avoidance and limiting any exposure underneath them. Poor visibility today will make it harder to locate the exisiting glide cracks in the terrain.

 

 

 

Glide avalanche on Seattle Ridge. We believe this released in the early morning yesterday.

 


Mountain Weather

Yesterday, cloudy skies in the morning gave way to mostly clear and sunny weather in the afternoon. Temperatures were in the mid-20Fs above 3000' and low 30Fs around 1000'. Winds from the ENE were in the teens throughout most of the day and then picked up to 30-40 mph range overnight. Gusts reached into the 70s this morning. .5" of precipitation (5'' of snow above 1500') fell overnight.

Today skies will be cloudy with a mixture of snow and rain as the storm continues. Precipitation is forecasted to be heavy at times. Up to an 1" of water (5-10" of snow) is possible. Temperatures will be in the high 20Fs to mid 30Fs. North to East winds, 25 to 30 mph decreasing in the afternoon. Additional rain/snow showers are expected overnight. 

This stormy pattern continues through the week as a low in the Gulf and associated strong frontal system effect the region. 

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 30   3 .5  92 
Summit Lake (1400')  29  0 29
Alyeska Mid (1700')  33  2.5 .25  73

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  23  ENE  25 74 
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 16, 2017 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Closed
Placer River: Closed
Skookum Drainage: Closed
Turnagain Pass: ClosedThanks all for a safe and fun season on the Chugach NF! Stay tuned for the 2017/18 season. #playsafe #snowtosealevel
Twentymile: Closed
Seward District
Carter Lake: Closed
Lost Lake Trail: Closed
Primrose Trail: Closed
Resurrection Pass Trail: ClosedResurrection Pass trail will be open to snowmachine use during the 2017/18 winter season.
Snug Harbor: Closed
South Fork Snow River Corridor: Closed
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
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