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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Graham Predeger  
Saturday, December 5th 2015
Created: Dec 5th 5:22 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.
1 Low Treeline / 1,000'-2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1 Low Below Treeline / Below 1,000' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
 Show the Complete North American Avalanche Danger Scale
Rossignol
Special Announcement

The 7th annual Alyeska Ski Patrol Auction (benefiting the avalanche canine program) is happening tonight at the Sitzmark in Girdwood.  Always a good party, this is not to be missed!

See latest Alaska Dispatch News article HERE for more information on missing skier Liam Walsh in Hatcher Pass.


The Bottom Line

Weak snow exists in upper elevations of the advisory area where the avalanche danger is MODERATE above 2500’.  As you move up in elevation a persistent weak layer can be found at the base of our snowpack and human triggered avalanches are possible.

All areas below ~2,500’ are exhibiting LOW avalanche danger as temperatures have stayed below freezing and snowfall has been modest and incremental over the last week.

**If northerly winds kick up today earlier than expected, we'll see shallow, sensitive wind slabs on slopes with a southerly tilt.**


Primary Concern

Observations yesterday point toward weak snow at the ground in the upper elevations (above 3,000’) that show significant potential to propagate.  We are unclear how widespread these basal facets are across the forecast zone and with no other red flags (recent avalanches, whumphing or shooting cracks) reported in nearly a week, our snowpack is sending us a bit of a mixed message this weekend.  It’s the kind of avalanche problem (persistent slab) that may not present itself until a skier finds the sweet spot and triggers an avalanche, potentially after several tracks on the slope. So, if the plan is to push into bigger, steeper, above treeline terrain today, it’ll be worth digging a quick pit to see if you can find loose, faceted snow at the very bottom of the snowpack.  Look for snow with the consistency of a handful of sugar and if found, recognize that as your weak interface.

                                    


Additional Concern

The snow quality right now is arguably the best it’s been in over a year so no doubt the usual zones in Turnagain will be crowded.  Keep other adjacent groups in mind as you are moving through the mountains today and maintain good backcountry etiquette.  Wear and know how to use your rescue gear, expose one person at a time on a slope, discuss potential consequences if a slope does slide and don’t ski on top of other parties.

8-10" of new snow made for great skiing at 3,000' on Sunburst ridge yesterday.  Keep in mind that If northerly winds kick up today earlier than expected, we'll see shallow, sensitive wind slabs on slopes with a southerly tilt given the substantial amount of loose snow available for transport.


Mountain Weather

Yesterday was again marked by mild weather throughout the forecast zone.  Temperatures were comfortable in the 20’s, winds very light out of the East and just a few intermittent snow showers throughout the day not really amounting to much accumulation.

Today we can expect more of the same with morning fog eroding to clearing skies throughout the day and no new precipitation.  The winds are expected to increase throughout the day and into this evening from the North but are not expected to be much above 20mph at ridgetops.  Temperatures will be in the low 20’s F at ridgetops and the high 20’s to low 30’s F at 1,000’.  Prepare for a couple more days of high pressure before our next shot of unsettled weather has the potential to move into the region next Tuesday/ Wednesday.

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880') 24  .1  23 
Summit Lake (1400') 20   0  .1  12
Alyeska Mid (1700')  26  0  0  19

 

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

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812')  18  NE  5 15 
Seattle Ridge(2400')  21  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: 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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