Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Friday, March 11th 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).
Today’s avalanche danger rating is LOW with pockets of MODERATE. Warm weather in the afternoon is affecting south aspects and causing a new wet snow concern. Deeper instabilities continue to be present, although this hazard is diminishing and probably only a concern in very shallow snow and steep terrain.
It’s only March, but sometimes it feels like April in the afternoon. Day after day we get the same stable weather, which is keeping avalanche concerns low. The latest developing issue is afternoon warming on sunny south aspects. The sun is still not very intense but is strong enough to begin melting and changing the surface snow. Afternoon point releases and skier-triggered sluffs are beginning to happen. Check out the graph below that illustrates the wild temperature swings in the mountains right now.
Keep this in mind in the afternoon on south facing slopes. The seemingly insignificant point releases can step down to create a slab avalanche under the right conditions. There have been a couple of heat induced slab releases in the Girdwood valley and Summit over the last few days.
The deeper weaknesses have mostly stopped bCNFAIC Staffing us, but still deserve some respect. It may still be possible to trigger a deeper slab release in areas of thin snow cover on steep terrain. The most recent avalanches that happened were on facets above the Thanksgiving Rain Crust. When we do get new snow this may become a problem again.
Encyclopedia of avalanche terms.
Sunny skies over the last 2 weeks continue today and for the foreseeable future. Nighttime low temperatures are close to zero, and daytime highs can reach the 30s. Wind is light to moderate. Watch for the Aurora Borealis, which has been visible the last 2 nights.
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 FRI MAR 11 2011
.TODAY…SUNNY. HIGHS IN THE LOWER 20S TO LOWER 30S. LIGHT WINDS.
.TONIGHT…CLEAR. LOWS ZERO TO 15 ABOVE…COOLEST INLAND. LIGHT
.SATURDAY…SUNNY. HIGHS IN THE LOWER 20S TO LOWER 30S. VARIABLE WIND
TO 10 MPH.
.SATURDAY NIGHT…CLEAR. LOWS 5 BELOW TO 20 ABOVE…COOLEST
INLAND. LIGHT WINDS.
.SUNDAY…MOSTLY SUNNY. HIGHS IN THE 20S. LIGHT WINDS EXCEPT
NORTH 10 MPH NEAR SEWARD.
.SUNDAY NIGHT…MOSTLY CLEAR. LOWS IN THE TEENS.
.MONDAY THROUGH TUESDAY…PARTLY CLOUDY. HIGHS 25 TO 35. LOWS
5 TO 15.
TEMPERATURE / PRECIPITATION
SEWARD 30 15 27 / 0 0 0
GIRDWOOD 28 12 29 / 0 0 0
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
Temperature 13 at 0600. Light to moderate wind from the east.
-2600′ Seattle Ridge Wx Station-
Temperature 13 at 0600. Winding gusting to 15 from the ESE.
-1800′ Center Ridge Wx Station-
Temperature 12 degrees at 0600. No new snow.