Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Thursday, February 24th 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).
The avalanche hazard rating is MODERATE due to recent wind slabs and deeper weak layers. Wind activity diminished yesterday, bringing the hazard back down from Considerable. Residual wind slabs remain possible for human triggers. Deep persistent instabilities are less likely but possible to trigger in shallow areas.
The snow and wind events over the last 5 days have finally quieted down. All recent reports from Turnagain Pass talk about highly wind affected snow at the surface. A quick look around shows areas with raised anti-tracks from the lighter density snow being eroded away from denser tracked snow. The last few days had areas of natural wind slab avalanche activity. That hazard still exists but will be declining over time as the slabs bond to the layers underneath.
See photo gallery for examples of recent wind slab avalanches.
The avalanches that are stepping down into older and deeper weak layers are becoming less frequent. This hazard still exists but is difficult to say how likely it is to trigger. It follows the same trend we’ve been talking about for the past couple months with likely trigger points in shallower zones.
The last snowfall was last weekend. Since then wind has dominated the region with strong ridgetop wind from the Northwest. Yesterday the wind diminished and skies were clear. Temperatures have been cold with a warming trend since yesterday. Clear skies are expected today with light wind. A chance of snow tonight and tomorrow.
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.
I 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-
500 AM AKST THU FEB 24 2011
.TODAY…PARTLY CLOUDY. HIGHS IN THE 30S. LIGHT WINDS EXCEPT NORTH
10 TO 15 MPH NEAR SEWARD.
.TONIGHT…INCREASING CLOUDS WITH A CHANCE OF SNOW AFTER MIDNIGHT.
LOWS 10 TO 25 ABOVE…COOLEST INLAND. VARIABLE WIND TO 10 MPH.
.FRIDAY…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS EXCEPT NUMEROUS
SNOW SHOWERS INLAND. SNOW ACCUMULATION UP TO 3 INCHES. HIGHS IN THE
LOWER TO MID 30S. WEST WIND 10 TO 20 MPH. NEAR SEWARD AND
WHITTIER…NORTH AND WEST WIND 10 TO 20 MPH INCREASING TO 20 TO 35
MPH IN THE AFTERNOON.
.FRIDAY NIGHT…PARTLY CLOUDY. ISOLATED SNOW SHOWERS IN THE
EVENING. LOWS 10 TO 20 ABOVE. NORTHWEST WIND 10 TO 15 MPH EXCEPT
NORTH 20 TO 35 MPH NEAR SEWARD. NEAR WHITTIER…WEST WIND 30 TO 45
MPH WITH GUSTS TO 55 MPH.
.SATURDAY…MOSTLY SUNNY. HIGHS IN THE LOWER TO MID 20S. NORTHWEST
WIND 10 TO 20 MPH EXCEPT NORTH 30 TO 40 MPH NEAR SEWARD. NEAR
WHITTIER…WEST WIND 30 TO 45 MPH WITH GUSTS TO 60 MPH.
TEMPERATURE / PRECIPITATION
SEWARD 34 24 36 / 0 30 30
GIRDWOOD 33 23 34 / 0 40 60
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
Temperature 21. Light wind from the West.
-2600′ Seattle Ridge Wx Station-
Temperature 24. Light wind from the North.
-1800′ Center Ridge Wx Station-
Temperature 22 degrees. No new snow.