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Avalanche Advisory

Turnagain Area Avalanche Advisory
Forecaster:   Wendy Wagner  
Monday, February 21st 2011
Created: Feb 21st 6:47 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.
 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, February 21th 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
There is a MODERATE avalanche danger today for soft and hard wind slabs on and off ridgelines and in cross loaded terrain. Triggering a fresh wind drift as well as lingering stiffer drifts formed over the weekend is a possibility. A MODERATE danger remains for triggering a deeper avalanche that breaks into the older weak layers in shallow snow cover areas.


AVALANCHE DISCUSSION
One human triggered soft slab avalanche was reported yesterday in the Turnagain Pass area. This was on the south face of Corn Biscuit and was estimated to be 20 wide and 4-5 deep. The slide was initiated while a skier was traversing away from a thin rocky area and noticed a large, 20 foot, shooting crack. CNFAIC Staffwise, we have not heard, or seen (albeit limited visibility), of any CNFAIC Staff avalanche activity from Sunday.

It seems as though the winds had their way with much of the snow over the weekend. Everything from soft settled powder, wind crusts with variable thicknesses, large drifts and sastrugi cover the surface. The main concerns for today are any new fresh wind drifts that may have recently formed or lingering wind slabs which developed over the weekend. Overnight, the winds remained fairly light with moderate gusts however, if they do increase as forecast, watch for developing sensitive fresh wind drifts on leeward steeper slopes. There is still plenty of snow for transport even though the surface has already seen a couple windy days. The older wind slabs, formed over the past couple days, are expected to be stiffer, more stubborn and harder to trigger today, most dangerous in steep rocky terrain. Also, any new drifts may be on slopes different than those loaded over the weekend considering the main flow has switched around to a more northerly direction. Keep an eye out for firm hollow-feeling snow and cracking around, or shooting from, your skis/board/sled.

It has been 7 days now since the last avalanche we know of broke into the deeper weak layers near the ground. However, we are still concerned with the poor structure we keep seeing in shallow snow cover areas (less than 2 meters in general). Until we get a large enough storm with significant water weight to stress these layers to the point of failure, we cannot expect them to heal anytime soon. It is a spooky MODERATE - lower probability, higher consequence. Steering clear of steep slopes in these areas is wise.

Encyclopedia of avalanche terms.

WEATHER ROUNDUP
Yesterday clouds and flurries covered most of our region and temperatures were in the teens with west to north winds gusting into the 20s. Overnight, the northwest winds remained light gusting into the 20s and temperatures slightly dropping into the low teens. Today winds are forecast to increase from predominantly the northwest, gusting into the 40s or more on the higher ridgelines. It looks like well have party cloudy skies with temperatures climbing into the 20s for the first time in several days.

ANNOUNCEMENTS
The Forest Service is installing winter use bridges across Granite creek in Turnagain Pass. Be aware of an ice road from the Lyon creek bridge south towards Johnson Pass on the West side of the highway. Heavy equipment will also be used in the area.

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 AKST MON FEB 21 2011

...STRONG WIND THROUGH TUESDAY EVENING NEAR WHITTIER...
.TODAY...PARTLY CLOUDY IN THE MORNING THEN BECOMING MOSTLY SUNNY.
HIGHS IN THE 20S. NORTHWEST WIND 15 TO 30 MPH EXCEPT WEST 40 TO
55 MPH NEAR WHITTIER.
.TONIGHT...MOSTLY CLEAR. LOWS 5 BELOW TO 15 ABOVE...COOLEST
INLAND. NORTHWEST WIND 15 TO 30 MPH EXCEPT WEST 30 TO 45 MPH NEAR
WHITTIER.
.TUESDAY...SUNNY. HIGHS IN THE LOWER TO MID 20S. NORTHWEST WIND
10 TO 25 MPH EXCEPT WEST 40 TO 55 MPH NEAR WHITTIER.
.TUESDAY NIGHT...MOSTLY CLEAR. LOWS 10 BELOW TO 15 ABOVE...COOLEST
INLAND. NORTHWEST WIND 15 MPH. NEAR WHITTIER...WEST WIND 30 TO 45
MPH DECREASING TO 15 TO 30 MPH AFTER MIDNIGHT.
.WEDNESDAY...PARTLY CLOUDY IN THE MORNING THEN BECOMING MOSTLY
CLOUDY. HIGHS IN THE MID 20S TO MID 30S. LIGHT WINDS. NEAR
WHITTIER...WEST WIND 10 TO 15 MPH IN THE MORNING BECOMING LIGHT.

TEMPERATURE / PRECIPITATION

SEWARD 28 17 24 / 0 0 0
GIRDWOOD 29 10 27 / 0 0 0



WEATHER STATION SUMMARY for Turnagain Pass:
-3800 Sunburst Wx Station-
Temperature 11F and increasing. North wind 5-10mph gusting to 20.
-2600 Seattle Ridge Wx Station-
Temperature 13F and increasing. North wind 5-10 gusting to 20.
-1800 Center Ridge Wx Station-
Temperature 16F and should increase. No 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: 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

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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