Turnagain Pass

Good morning backcountry travelers this is Lisa Portune with the Chugach National Forest Avalanche Information Center on Sunday, January 10th at 7am. This will serve as a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (advisory does not apply to highways, railroads, or operating ski areas).

WEATHER ROUNDUP

No new snow fell in the last 24 hours in Turnagain Pass and Summit Lake. Yesterday ridgetop winds averaged 10-25mph out of the east and southeast while mountain temperatures were downright tropical in the mid to upper 30’s. As of 4 am this morning, ridgetop winds in Turnagain Pass are averaging 10-20mph out of the east and southeast while Summit Lake is a bit stronger at 20-25mph out of the southeast. Temperatures currently range from 29F at 3800 feet to 23F at sea level with a band of temps in the low 30’s at the mid elevations. Expect sunny skies today, fog down low, and slightly cooler alpine temperatures in the upper 20’s to low 30’s. We could get some strong gusty winds today from a strong occluded front and shortwave moving northward.

-The Center Ridge Wx Station at 1800 feet/Turnagain Pass-

recorded no new snow in the last 24 hours. The current temp is 31F (4 degrees colder than yesterday) with a total snowpack depth of 56 inches.

-The Sunburst Wx Station at 3800 feet/Turnagain Pass-

recorded light to moderate easterly winds yesterday averaging 10-25mph with gusts in the 30’s. The current temp is 29F (2 degrees colder than yesterday) with winds averaging 5-10mph out of the east.

-The Summit Lake Wx Station at 1200 feet-

recorded no new snow in the last 24 hours. The current temp is 28F (5 degrees colder than yesterday) with a total snowpack depth of 29 inches.

-The Fresno Ridge Wx Station at 3400 feet/Summit Lake-

recorded moderate southeasterly winds yesterday averaging 15-25mph with gusts in the 30’s and 40’s. The current temp is 28F (3 degrees colder than yesterday) with winds averaging 20-25mph out of the southeast.

The weather forecast for:

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKST SUN JAN 10 2010

.TODAY…PARTLY CLOUDY. AREAS OF FOG REDUCING VISIBILITIES TO ONE

HALF MILE AT TIMES THROUGH PORTAGE VALLEY AND TURNAGAIN ARM THIS

MORNING. HIGHS IN THE MID 20S TO UPPER 30S…COLDEST

INLAND. NORTH WINDS INCREASING 15 TO 30 MPH WITH GUSTS TO 40 MPH

NEAR SEWARD LATER THIS MORNING. WINDS INCREASING TO WEST 15 TO 30 MPH

NEAR WHITTIER THIS AFTERNOON. VARIABLE WINDS 5 TO 15 MPH ELSEWHERE.

.TONIGHT…MOSTLY CLEAR. LOWS 10 TO 25 ABOVE…COLDEST INLAND.

NORTH WINDS 15 TO 30 MPH WITH GUSTS TO 40 MPH NEAR SEWARD. WEST WIND

15 TO 30 MPH NEAR WHITTIER. VARIABLE WINDS 5 TO 15 MPH ELSEWHERE.

.MONDAY…MOSTLY CLOUDY WITH A SLIGHT CHANCE OF SNOW. HIGHS IN

THE MID 20S TO MID 30S…COLDEST INLAND. NORTH WINDS 15 TO 30 MPH

WITH GUSTS TO 40 MPH NEAR SEWARD. WEST WIND 15 TO 30 MPH NEAR

WHITTIER. VARIABLE WINDS 5 TO 15 MPH ELSEWHERE.

TEMPERATURE / PRECIPITATION

SEWARD 37 26 35 / 0 0 20

GIRDWOOD 28 15 26 / 0 0 0

AVALANCHE DISCUSSION

Today, a LOW avalanche danger exists on all slopes which means that natural and human-triggered avalanches are unlikely. There is not much snow for the wind to move around these days, but you may find small pockets of sensitive windslab above 2500 feet in isolated areas like steep windloaded couloirs or crossloaded gullies. We are looking at generally stable avalanche conditions, but as always, evaluate the snow and terrain carefully and always use good travel habits.

You know it’s an El Nino winter when crampons become the tool of choice for ascending instead of skins. The rain line reached almost 3000 feet this past week as evidenced by the monster roller balls present between 2600 and 2800 feet elevation. A few small point release wet slides happened during the rain event midweek, but that’s about it for recent avalanche activity. We continue to find various instabilities in the top 6-12 inches at the higher elevations, but they have not been reactive to skiers or riders. These weak layers include old buried facets, decomposing stellar crystals, and density changes between windslabs. Below 2200 feet, the old buried surface hoar from the second week of December is buried 1-1.5 feet down and has not been especially reactive in our stability tests. As far as skiing and riding conditions…we’re looking at boilerplate as well as breakable crust below 2600 feet, fast carvable dense snow and hardslab above 2600 feet, and windhammered ridges.

There are a few glide cracks lingering throughout Turnagain Pass, most notably on the south aspects of Tincan and Eddies and just north of the snowmachine uptrack on Sunnyside. One on the south side of Eddies decided to pop out early this past week for whatever reason (see our photo gallery). These things are unpredictable at best so stay out from under them.

Some Summit Lake observations…Alex found 3 separate layers of small buried surface hoar in the top 1.5 feet sandwiched in between hard windslabs at 2700 feet on a south aspect of Fresno Ridge. They were not especially reactive in his isolated column stability tests (CT22,23 both Q2’s), but they are still layers of concern.

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.