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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Friday, January 31st 2014
Created: Jan 31st 6:39 am
2 Moderate Alpine / Above 2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
2 Moderate Treeline / 1,000'-2,500' Travel Advice: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.
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 Bottom Line

The avalanche danger is MODERATE both above and below treeline:

Above treeline - On all aspects above 3,000' in elevation the possibility remains for triggering a deep slab avalanche. This type of avalanche is becoming harder to trigger, yet if one does release it could break full-depth and be unsurvivable. Wind slab avalanches are also possible at this elevation zone and should be shallow and fairly easy to identify. Watch for areas with wind drifted snow.

Below treeline - In areas below 3,000' the snowpack is freezing from the surface downward. However, wet and weak snow still remains below the surface crust. Triggering a wet slab avalanche has decreased significantly but until we have a solid refreeze on all aspects it cannot be completely ruled out. 

Even though the cool weather is helping to stabilize the snowpack, don't forget to use safe backcountry travel protocols. For example, only exposing one person at a time and always have an escape route planned.


Primary Concern

With the sunny skies and increasing daylight hours, travel to the upper elevations in search of dry snow may be on some folk's mind (if you are willing to brave the crust in order to get there - and back). Snow cover above 3,000' has greatly improved after the January onslaught and is capped with 4-6" of soft snow. The exceptions are those areas that avalanched to the ground. The last known deep slab was six days ago on Goat Mtn.

The reason we had such a widespread large avalanche cycle with slides breaking full-depth was because of weak snow near the ground that formed in November and December. We are four days past the end of the cycle yet it is still uncertain how well the weak faceted snow is adjusting to the new load. We know it is buried over 3 feet deep and likely much deeper in areas. This makes triggering a deep slab avalanche hard but it is not out of the question. Thin spots in the slab are the most likely trigger areas and can be commonly found near rocks and scoured terrain features.


Secondary Concern

Though the deep slab problem is by far the most concerning due to the potential consequences, wind slabs will be the most likely avalanche issue encountered above 3,000 feet. We found a few of these yesterday on all aspects yet they were quite small (around 2" thick and 10' wide). They were very reactive however and if you are traveling in the upper elevations where dry snow exists, I'd be on the lookout for any fresh wind deposited snow, especially that which is sitting on a slick surface. 


Additional Concern

With almost three days now of below freezing temperatures the pack is developing a healthy crust on the surface. These conditions are confined to elevations below 3,000'. Yesterday we dug (or maybe chopped is a better word) into the crust at 2,500' and found it to be 1 foot thick. Underneath it remains 1-2 feet of wet and weak snow. The area we looked at yesterday was shaded and a place suspected to have a thicker crust than southerly slopes where Kevin dug two days ago. Check out Kevin's video that shows just how weak the wet snow is.

This 'hole' (akin to an ice fishing hole) give a sense of the thick crust over wet snow situation (2,500', W aspect).

 

Though the crust is getting thicker by the day and triggering a wet slab avalanche below treeline is becoming unlikely, we do have an unusual set up. As the ol' timers say - unusual things can happen with unusual situations. Wet slabs with a crust on the surface have occurred before.

All that said, the greatest hazard below 3,000' is slide for life conditions. 

 


Mountain Weather

Yesterday's weather consisted of blue bird skies, cool temperatures and light Northwest winds. Temperatures at 1,000' were in the mid 20's F and the upper teens at 4,000'.

Today is expected to be very similar. Skies have remained clear overnight, excect for some patchy fog in low-lying areas. A slight inversion is setting in and temperatures this morning at sea level and the ridgetops are both in the mid 20's F. We should see a slight warm up to around 30F below treeline during the day. Winds are expected to remain around 10mph on ridgetops from the Northwest.

As for the extended forecast - it looks like this blocking high pressure will remain over mainland Alaska through the weekend.

Warmest January on record? With two weeks of rainy weather and at least one all time high temperature in the Girdwood Valley, we may just break the record for the warmest January. More on this in the next couple days.

 

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: Mar 28, 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: OpenPlacer remains open but SKOOKUM DRAINAGE will close to motorized use on April 1st.
Skookum Drainage: OpenSKOOKUM DRAINAGE CLOSES TO MOTORIZED USE ON APRIL 1 annually as per the Chugach National Forest Plan document.
Turnagain Pass: Open
Twentymile: Open
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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