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Turnagain Area Avalanche Advisory
Wednesday, April 14th 2010 6:35 am by CNFAIC Staff
ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.
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BROUGHT TO YOU BY
The Bottom Line
Good morning backcountry travelers this is Matt Murphy with the Chugach National Forest Avalanche Information Center on Wednesday April 14th, 2010 at 7 am. 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).

ANNOUNCEMENTS
Skookum Valley and Skookum Glacier are closed to motorized vehicles (snowmachines, helicopters, ATVs) except for subsistence uses.. This closure is directed in the current Chugach National Forest Land and Resource Management Plan. Placer River Drainage remains open for motorized use to Spencer Glacier.

WEATHER ROUNDUP
-The winds are moderate this morning averaging 16-21mph with some strong gusts up to 31mph down on Seattle Ridge
-The 24 hour snotel sites are reporting:
-0.1 inches of water, 4 of melting/settlement at 1800 at Turnagain Pass
-0.1 inches of water, 3 of melting/settlement 1100 at Grandview
-0.1 inches of water, 2 of melting/settlement at 1400 at Summit Creek.
-This mornings (5am) radars are full of precip with the majority missing our location and heading east of Cordova
-Temps are starting off about the same this morning at most weather stations as they did yesterday morning. Above freezing temps made it up to 33 degrees at 2600 yesterday. This mornings temperature range is 33 degrees F at sea-level and 22 degrees F at 3800.



AVALANCHE DISCUSSION
Todays avalanche danger is LOW with pockets of MODERATE. Small human-triggered avalanches will be possible on isolated wind slabs sitting on top of a crust with buried surface hoar/facets on top of that crust.

Surface hoar was observed on Tincan, Pastoral, Twin Peaks, and Petes North, and Cornbiscuit at the end of last week. On Sunday we found this surface hoar buried and standing up on a small wind lip on Tincan. This small pocket was very reactive to human triggers. Monday, we tried to confirm this same layer of buried surface hoar on Sunburst, but could not find it. We did, however, find facets on top of the most recent sun crust instead of the surface hoar. Recent observations have described this surface hoar as large above 3200 (up to 1cm).

Yesterday's sun pre-cooked a lot of the surface snow. We observed lots of small point release avalanches on sun affected slopes. Only a couple of spots entrained enough snow to become medium sized avalanches. Some new glide crack avalanches were reported in Placer Valley.

The sun is the critical watch out situation this time of year. April sun and temps can change the snowpack much more drastically than January or February sun. Avalanche danger can increase quickly during periods of rapidly warming temps and direct sunlight; especially, when the sun hits fresh snow.

Glide cracks are secondary concern today. These crevasse like features are those cracks that go all the way to the ground. Avoid traveling underneath these cracks. Glide cracks and full depth release avalanches have been occurring on warm sunny days. We are seeing more and more of these glide cracks form everyday.

WEATHER FORECAST (National Weather Service)
WESTERN PRINCE WILLIAM SOUND-
INCLUDING...WHITTIER...SEWARD...GIRDWOOD...MOOSE PASS
500 AM AKDT WED APR 14 2010

.TODAY...SNOW AND RAIN. SNOW ACCUMULATION 1 TO 4 INCHES. HIGHS IN THE
30S TO NEAR 40. SOUTH TO EAST WINDS 10 T0 20 MPH.
.TONIGHT...SNOW IN THE EVENING...THEN A CHANCE OF SNOW SHOWERS AFTER
MIDNIGHT. SNOW ACCUMULATION UP TO 1 INCH. LOWS IN THE LOWER 20S TO
LOWER 30S. LIGHT WINDS EXCEPT SOUTH 15 MPH NEAR SEWARD IN THE
EVENING.
.THURSDAY...SKIES BECOMING PARTLY CLOUDY. A CHANCE OF SNOW SHOWERS IN
THE MORNING. HIGHS AROUND 40. LIGHT WINDS EXCEPT WEST 10 TO 15 MPH
NEAR WHITTIER.

TEMPERATURE / PRECIPITATION
SEWARD 41 28 42 / 100 70 0
GIRDWOOD 40 26 40 / 100 90 20


Short Term Weather Model Forecasts (NAM, WRF, GFS) for the Kenai Mountains near Turnagain Pass
Sea-level: temps are forecasted between 26-40 and between 0.1-0.25 of water forecasted
3000: temps are forecasted in the range of 23-32 degrees F with winds 5-10 mph
6000: temps are forecasted in the range of 14-23 degrees F with winds 5-10 mph

WEATHER STATION SUMMARY for last 24 hours at TURNAGAIN PASS
3800-Sunburst Wx Station
Temp (5am): 22 (same as yesterday morning)
Winds: In last 24 hours winds have been light-moderate averaging 6-20mph with a strong max gust of 37mph
HIGH TEMP of 29 at 1pm

2600-Seattle Ridge Wx Station
Temp (5am): 25 (same as yesterday morning)
Winds: In last 24 hours have been light to moderate averaging 5-21 mph with a strong max gust of 31mph
HIGH TEMP of 33 between 4-5pm

1800-Center Ridge Wx Station
Temp (5am): 29 (1 degrees warmer than yesterday morning)
Precip: 0.1 inches of water, 4 inches melting/settlement
HIGH TEMP 43 between 4-6pm

Thanks for checking todays avalanche advisory. The next one will be posted tomorrow Thursday April 15th, 2010.


 Show the Complete North American Avalanche Danger Scale
1 Low Alpine / Above 2,500' Travel Advice: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
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.

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 20, 2019 )

AREA STATUS WEATHER AND RIDING CONDITIONS
Glacier District
Johnson Pass: Open
Placer River: ClosedClosed as of 3.20.19 due to lack of snow.
Skookum Drainage: ClosedPlacer access closed as of 3.20.19 due to lack of snow.
Turnagain Pass: Open
Twentymile: ClosedClosed as of 3.20.19 due to lack of snow.
Seward District
Carter Lake: Open
Lost Lake Trail: OpenPlease stay on trail to avoid resource damage through forested areas.
Primrose Trail: OpenPlease stay on trail to avoid resource damage through forested areas.
Resurrection Pass Trail: ClosedClosed for the 2018/19 season. Next season will be open to motorized use.
Snug Harbor: Open
South Fork Snow River Corridor: ClosedClosed as of 3.20.19 due to lack of snow.
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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