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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Kevin Wright  
Friday, April 8th 2011
Created: Apr 8th 6:53 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
Silverton Mountain Guides
The Bottom Line
Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Friday, April 8th 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
Todays avalanche danger rating is CONSIDERABLE for storm snow and wind slab over weak layers of buried surface hoar and sun crusts. The intensity of the storm has diminished but the avalanche hazard will continue to be elevated. Expert avalanche skills are essential for safe travel in the backcountry today.

AVALANCHE DISCUSSION
With the storm peaking yesterday we dont have a thorough understanding of how our snowpack reacted to the additional load. If the conditions allow it, we will get onto the upper slopes today to do a damage assessment.

A lot of our information yesterday came from remote weather stations. Girdwood received a solid 18-24 inches at higher elevations. Turnagain pass seemed to be well under those amounts, but some areas could be similar. Regardless of exact snowfall numbers, it was a significant shock to an already touchy snowpack. There were undoubtedly natural avalanches happening during the storm. As the storm backs off, the natural activity will die down and our concern shifts to human triggered avalanches.

Wednesdays skier and snowmachine triggered avalanches (including a full burial) are an indicator that many slopes were ripe to avalanche. After new snow and wind many of the remaining slopes will be either spoiled (avalanched naturally) or close to rotten (ready for the trigger to avalanche). Check the photo gallery for a couple new photos we received yesterday.

There is no doubt in my mind that human triggered avalanches are likely today. Terrain management is key to staying safe. Steeper, higher elevation slopes will be dangerous unless they already slid during the storm.

Encyclopedia of avalanche terms.

WEATHER ROUNDUP
The storm peaked yesterday and wind and snowfall both dropped off significantly by 5pm. Highest intensities had snowfall 1-2 inches per hour and wind gusting to near 80mph at the ridge tops. Snow accumulation reached 2 feet in some areas but is very regionally dependent. Today 2-6 inches of snow is predicted with moderate wind from the SE.

Wendy 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 FRI APR 8 2011
.TODAY...RAIN AND SNOW SHOWERS. LITTLE OR NO SNOW ACCUMULATION. HIGHS
IN THE MID 30S TO LOWER 40S. SOUTHEAST WIND 10 TO 15 MPH EXCEPT
SOUTHEAST 20 TO 35 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
.TONIGHT...SNOW AND RAIN SHOWERS IN THE EVENING...THEN NUMEROUS SNOW
SHOWERS AFTER MIDNIGHT. SNOW ACCUMULATION UP TO 2 INCHES. LOWS IN THE
LOWER 20S TO MID 30S. EAST WIND 10 TO 15 MPH WITH GUSTS TO 25 MPH
ALONG TURNAGAIN ARM AND PORTAGE VALLEY IN THE EVENING.
.SATURDAY...MOSTLY CLOUDY. SCATTERED RAIN AND SNOW SHOWERS. HIGHS IN
THE MID 30S TO LOWER 40S. LIGHT WINDS.
.SATURDAY NIGHT...MOSTLY CLOUDY. SCATTERED SNOW AND RAIN SHOWERS IN
THE EVENING...THEN ISOLATED SNOW SHOWERS AFTER MIDNIGHT. LOWS IN THE
MID 20S TO MID 30S. LIGHT WINDS EXCEPT NORTH 15 TO 20 MPH NEAR
SEWARD.
.SUNDAY...MOSTLY CLOUDY. ISOLATED SNOW SHOWERS IN THE MORNING...
THEN ISOLATED SNOW AND RAIN SHOWERS IN THE AFTERNOON. HIGHS IN THE
MID 30S TO LOWER 40S. LIGHT WINDS EXCEPT NORTH 15 MPH NEAR SEWARD.
.SUNDAY NIGHT...CLOUDY WITH ISOLATED SNOW SHOWERS. LOWS IN THE
20S.

TEMPERATURE / PRECIPITATION

SEWARD 41 28 43 / 100 70 40
GIRDWOOD 41 22 43 / 100 80 40


WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
Currently 21 degrees. Wind gusting into the 20s from the East.
-2600 Seattle Ridge Wx Station-
25 degrees at 6am. Wind to the mid teens from the Southeast.
-1800 Center Ridge Wx Station-
28 degrees at 6am. 4 inches of snow and 0.5 inches of water equivalent measured yesterday.


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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