Turnagain Pass

Good morning backcountry travelers this is Lisa Portune with the Chugach National Forest Avalanche Information Center on Sunday, January 16th 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).

ANNOUNCEMENTS

We’re starting an incentive program to encourage everyone to submit snow and avalanche observations. Each quality observation will earn you one chance to win a monthly prize. At the end of this season all the submissions will go into a drawing for an avalanche beacon of your choice. Thanks for all the great work, and keep sending in those observations!

BOTTOM LINE

The avalanche danger rating remains at MODERATE today. Human triggered avalanches are still possible, especially in shallow areas of the snowpack where our persistent weak layers are closer to the surface and more easily affected by the weight of a skier or rider. Areas of sensitive windslab may also exist near ridgetops and in crossloaded terrain. While the likelihood of triggering an avalanche continues to decline, areas of instability still lurk out there if you look hard enough.

AVALANCHE DISCUSSION

We received a report of a close call on Cornbiscuit that happened a few days ago. A snowboarder triggered an avalanche on the south face about half way down where the slope rolls over. He was caught and carried but luckily able to right himself and swim/crawl out of the flow of debris. He estimated that the slide ran about 1000 feet and was 50 feet wide by 1 foot deep. We are not sure what weak layer this avalanche failed on, but the rider noticed that Cornbiscuit was especially wind-affected and that tracks from the day before were blown over. AnCNFAIC Staff party reported hollow sounding hard windslab with well developed facets underneath on the south end of Turnagain Pass by Twin Peaks. They decided not to ski certain slopes and returned the way they came.

While snowpit stability tests are showing little to no reactivity, and the frequency of human-triggered avalanches has declined this past week, the poor structure of our snowpack still demands caution…especially in steeper terrain. Our weak layers consist of numerous layers of buried surface hoar that formed in December, facets above and below the Thanksgiving Rain Crust (TRC), and sugary faceted snow below recent windslab. Predicting where you could trigger an avalanche is especially tricky right now, so use good travel techniques to minimize the hazard. Keep in mind that most of the larger natural and human triggered avalanches that happened the first week of January failed on a layer of buried surface hoar and then stepped down to the deeper facets around the TRC.

Snow conditions right now are variable. Last week’s sporadic winds hit the higher elevations and passes where you’ll find dense windslab, exposed ice crusts, dust on crust, and wind-buffed powder. More protected areas down low hold softer snow and monster sized surface hoar (see photo below).

Photo by Bob Sutherland

Encyclopedia of terms: www.fsavalanche.org/Encyclopedia.aspx

WEATHER ROUNDUP

It has been 11 days since our last snowfall…enough already La Nina! In the last 24 hours, ridgetop winds averaged 5-15mph out of the north and west while temps continued to drop. Temperatures this morning range from -7F at sea level to -12F at the higher elevations. The cold sink this morning is Summit Lake at -21F. Expect continued sunny skies today, 10mph winds out of the north and west, and the coldest temps of the winter so far.

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:

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKST SUN JAN 16 2011

…STRONG WIND THROUGH EARLY THIS EVENING NEAR WHITTIER…

.TODAY…SUNNY. HIGHS ZERO TO 10 BELOW EXCEPT 5 TO 10 ABOVE ALONG

THE COAST. NEAR WHITTIER…SOUTHWEST WIND 25 TO 35 MPH WITH GUSTS

TO 60 MPH. NEAR SEWARD…NORTH WIND 20 TO 30 MPH WITH GUSTS TO 40

MPH. ELSEWHERE…NORTHWEST WIND TO 10 MPH.

.TONIGHT…CLEAR. LOWS 10 BELOW TO 25 BELOW EXCEPT ZERO TO 5 ABOVE

ALONG THE COAST. NEAR WHITTIER…SOUTHWEST WIND 25 TO 35 MPH WITH

GUSTS TO 45 MPH DECREASING TO 15 TO 25 MPH AFTER MIDNIGHT. NEAR

SEWARD…NORTH WIND 20 TO 35 MPH DECREASING TO 10 TO 20 MPH AFTER

MIDNIGHT. ELSEWHERE…VARIABLE WIND TO 10 MPH.

.MARTIN LUTHER KING JR DAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW

SHOWERS. HIGHS 10 BELOW TO 5 ABOVE EXCEPT AROUND 15 ALONG THE

COAST. NORTH TO WEST WIND TO 15 MPH.

TEMPERATURE / PRECIPITATION

SEWARD 8 2 15 / 0 0 40

GIRDWOOD 0 -8 4 / 0 0 30

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

recorded winds averaging 2-9mph out of the west the last 24 hours. Temps dropped from a high of 2F yesterday to the current temp of -8F.

-2600′ Seattle Ridge Wx Station-

recorded winds averaging 2-13mph out of the north the last 24 hours. Temps dropped from a high of 3F yesterday to the current temp of -12F.

-1800′ Center Ridge Wx Station-

recorded no new snow the last 11 days. Temps dropped from a high of 3F yesterday to the current temp of -11F.