Turnagain Pass

Good morning backcountry travelers this is Jon Gellings with the Chugach National Forest Avalanche Information Center on Wednesday, December 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).

ANNOUNCMENTS

This weekend, December 11-12, there will be an Interagency Avalanche Rescue Training taking place at Turnagain Pass. Alaska Mountain Rescue Group, Alaska Search and Rescue Dogs, Alaska State Troopers, Nordic Ski Patrol, and US Forest Service will be some of the agencies participating in this two day event. There will be scenarios on both the motorized and non-motorized sides of Turnagain Pass. The parking lot on the eastern side of the Seward Highway will still be open to the public, but will also be the location for the staging area for this training exercise. There will be some helicopter use in the area for the purpose of this training event. If you have any comments or concerns, please contact Matt Murphy by phone at 907-754-2349 or email at mattmurphy@fs.fed.us. Thank you for your cooperation with this important safety training.

WEATHER ROUNDUP

It was feeling pretty warm yesterday when we were up on Sunburst digging in the snow. At 12:15, the temperature where we were at was 34F. We were also seeing a tiny amount of freezing rain falling as we drove out of Turnagain Pass. Today, it is looking like temperatures will cool down and skies will clear up. The Low pressure which has been giving us cloudy skies and small amounts of precipitation over the past few days is still in the Gulf of Alaska, but there is no cloud band above us right now. All radar images are currently clear, and satellite images are clear as well. Insignificant amounts of wind are forecasted today, although areas near Whittier are forecasted to receive strong winds through tomorrow afternoon.

AVALANCHE DISCUSSION

Today the avalanche hazard is MODERATE. Small to medium sized human-triggered avalanches

1-2 feet deep are still possible on steep windloaded slopes, while Natural avalanches are unlikely. Use caution on steep, unsupported, and convex terrain near ridgetops and in crossloaded gullies.

Although no new avalanches have been observed or reported since last Saturday, the possibility still exists to trigger an avalanche in many areas of Turnagain Pass and the surrounding areas. Our biggest instability is due to a buried layer of surface hoar that formed between Thanksgiving and December 3rd. Underneath the surface hoar is 6 inches of low density faceted snow, which in turn is sitting on the dreaded Thanksgiving Rain Crust. Underneath this crust, we are seeing mixed forms of snow, including facets. Failures on both the surface hoar layer and in the facets were fairly low energy (Q2-3)and showing moderate to high strength (2xCT & ECTN 12-23). The new snow in upper elevations and steep terrain is starting to settle into a slab, but was not propagating fractures in our pit yesterday. Our primary concern today is mainly on any steep, windloaded slopes up high where the surface hoar and rain crust are buried under a dense slab of snow.

Whumphing sounds have also been reported over the past several days on Eddies, Tincan, and Center Ridge. Shooting cracks have not been observed since Sunday on Tincan, and were breaking down to the layer of buried surface hoar. One of our observers reported no signs of instability on Sunday while snowmachining in Main Bowl on the backside of Seattle Ridge. He also watched a skier on Widowmaker Peak where the new snow only sluffed on the layer of surface hoar. This layer is tricky to figure out where it is located, so be mindful of it if you are heading into more committing terrain today.

Glide cracks and avalanches are not showing much activity recently, but do not forget about where you have seen them. They could be located under thin layers of snow, much like crevasses on a glacier. A person riding in the vicinity of a crack could potentially fall through a weak snow cover and into a crack, so be extra cautious on your descent.

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-

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKST WED DEC 8 2010

…STRONG WINDS THROUGH THURSDAY AFTERNOON NEAR WHITTIER…

.TODAY…MOSTLY SUNNY. HIGHS IN THE MID 20S TO UPPER 30S…

COOLEST INLAND. NORTH WIND 25 TO 35 MPH NEAR SEWARD. WEST WIND 20 TO

35 MPH WITH GUSTS TO 50 MPH NEAR WHITTIER. VARIABLE WIND 10 MPH

ELSEWHERE.

.TONIGHT…MOSTLY CLEAR. LOWS 15 TO 30 ABOVE…COOLEST INLAND.

NORTH WIND 25 TO 35 MPH NEAR SEWARD. WEST WIND 20 TO 35 MPH WITH

GUSTS TO 50 MPH NEAR WHITTIER. VARIABLE WIND 10 MPH ELSEWHERE.

.THURSDAY…MOSTLY SUNNY. HIGHS IN THE MID TEENS TO LOWER 30S…

COOLEST INLAND. NORTH WIND 20 TO 30 MPH NEAR SEWARD. WEST WIND 20 TO

30 MPH WITH GUSTS TO 45 MPH NEAR WHITTIER. VARIABLE WIND 10 MPH

ELSEWHERE.

TEMPERATURE / PRECIPITATION

SEWARD 34 24 28 / 0 0 0

GIRDWOOD 23 15 16 / 0 0 0

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

recorded light Northeast winds yesterday averaging 5-10mph and temps ranging from 26F to 30F. The current temp is 27F with light winds now coming out of the Northwest.

-2600′ Seattle Ridge Wx Station-

winds started working again yesterday, but then stopped working several hours later. It recorded temps ranging from 27F to 30F yesterday. The current temp is 27F.

-1800′ Center Ridge Wx Station-

recorded no new snow in the last 24 hours. Current total snow depth is 51 inches. Temps yesterday ranged from 29F to 33F. The current temp is declining at 22F.