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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Monday, April 4th 2011
Created: Apr 4th 6:54 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.
3 Considerable Below Treeline / Below 1,000' Travel Advice: Dangerous avalanche conditions. Careful snowpack evaluation, cautious routefinding and conservative decision-making essential.
 Show the Complete North American Avalanche Danger Scale
The Bottom Line
Good morning backcountry travelers. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Monday, April 4th at 7am. This will serve as 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).

BOTTOM LINE
Today the avalanche danger is CONSIDERABLE for both slab avalanches breaking into weak layers 2-5 feet deep and wind slabs formed in yesterdays new snow. There is also a MODERATE danger for soft slab avalanches in the storm snow. If skies break up keep a close eye on any avalanchs from yesterday as this is bulls eye data for slopes that are still prone to slide.

AVALANCHE DISCUSSION
Yesterdays storm has slowed down. By the afternoon 14-16 inches of heavy snow accumulated at and below tree line on Turnagain Pass while Girdwood Valley picked up around 8-12 inches. The limited visibility kept travel in, and viewing of, higher elevations restricted. We are uncertain as to what yesterdays high winds and new snow have produced for avalanches. What we do know is small, heavy, 12-16 deep soft slabs were breaking on the steeper rollovers below tree line. These soft slabs will likely be less sensitive today as the storm snow bonds and gains strength.

Most of the action is above tree line and the primary concern for today remains the buried weak layers which now sit under 2-5 of snow. These weak layers are persistent and have produced significant avalanches after the March 25th storm, the March 29th storm and, until proven innocent, likely yesterdays April 3rd storm. Northerly aspects, with minimal to no crusts in the upper few feet of snow, are the most concerning. Watch for recent deeper avalanches as well as whoomphing sounds. Steering clear of steeper slopes today is recommended.

The CNFAIC Staff concerns for today will be wind slabs that developed with the strong winds and soft slabs in the storm snow. Though these are likely to be less reactive with the warm temperatures and decrease in winds overnight, dont count on it yet, they can still be sensitive to human triggers, especially as elevation increases. Shooting cracks will be something to watch for.

Take home for today: If skies open up enough to venture into the upper elevations high level snow assessment skills will be required for safe travel. Keep a close eye on any recent avalanches from yesterday. These will be bulls eye data that slopes are potentially unstable. Particularly, steering clear of aspects and angles with recent slab avalanche activity is prudent.


Encyclopedia of avalanche terms.

WEATHER ROUNDUP
Snow showers continued yesterday with limited visibility, a total of 12-16" of high density snow fell below 2300' (likely more at higher elevations) near Turnagain Pass with Girdwood Valley 8-12 and the Summit Lake area only a few inches. Winds were light in sheltered locations while gusts around 50mph were reported from the ridgetop weather stations. Temperatures were in the mid 30's at 1500' and low 20's around 3500'. Overnight, the snow and winds have let up while the temperature did not drop. Today lingering snow showers and cloudy skies remain with a chance to pick up a few more inches. Winds will be gusting to 30mph from the NE while temperatures will be on the rise well into the 30's and 20's at upper elevations with the rain-snow line near 1300.

Jon will issue the next advisory tomorrow morning at 7am. If you get out in the backcountry give us a call at 754-2369 or send us your observations using the button at the top of this page. Thanks and have a great day.

The NWS weather forecast for:
WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKDT MON APR 4 2011
.TODAY...NUMEROUS SNOW AND RAIN SHOWERS IN THE MORNING BECOMING
NUMEROUS RAIN SHOWERS IN THE AFTERNOON. SNOW ACCUMULATION UP TO 2
INCHES. HIGHS IN THE MID 30S TO MID 40S. SOUTH TO EAST WIND 15 MPH.
THROUGH PORTAGE VALLEY AND TURNAGAIN ARM...SOUTHEAST WIND 10 MPH
INCREASING TO 25 MPH IN THE AFTERNOON.
.TONIGHT...SNOW AND RAIN LIKELY IN THE EVENING...THEN SNOW LIKELY
AFTER MIDNIGHT. SNOW ACCUMULATION UP TO 3 INCHES. LOWS IN THE
LOWER 20S TO MID 30S. SOUTHEAST WIND 15 TO 30 MPH.
.TUESDAY...SNOW IN THE MORNING...THEN SNOW AND RAIN IN THE AFTERNOON.
SNOW ACCUMULATION UP TO 2 INCHES. HIGHS IN THE MID 30S TO LOWER 40S.
SOUTH WIND 15 MPH BECOMING VARIABLE IN THE AFTERNOON.
.TUESDAY NIGHT...NUMEROUS SNOW AND RAIN SHOWERS IN THE EVENING...THEN
SCATTERED SNOW SHOWERS AFTER MIDNIGHT. LOWS IN THE MID 20S TO MID
30S. VARIABLE WIND TO 10 MPH. NEAR WHITTIER...LIGHT WINDS BECOMING
WEST 10 TO 20 MPH AFTER MIDNIGHT.
.WEDNESDAY...PARTLY CLOUDY. HIGHS IN THE LOWER 30S TO LOWER 40S...
COOLEST INLAND. NORTHWEST WIND 10 TO 15 MPH EXCEPT WEST 15 TO 30 MPH
NEAR WHITTIER.
.WEDNESDAY NIGHT...MOSTLY CLOUDY. LOWS 25 TO 35.
.THURSDAY...MOSTLY CLOUDY WITH A CHANCE OF RAIN. HIGHS 35 TO 45.

TEMPERATURE / PRECIPITATION

SEWARD 42 30 40 / 60 60 80
GIRDWOOD 44 35 43 / 60 60 80


WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
24 degrees. East wind 6mph gusting 11mph.
-2600 Seattle Ridge Wx Station-
27 degrees. SE wind 11mph gusting 14mph.
-1800 Center Ridge Wx Station-
30 degrees. Trace of new snow.


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 15, 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: Open
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

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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