Turnagain Pass

Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Friday, February 4th 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).

BOTTOM LINE

The avalanche hazard rating is CONSIDERABLE. Yesterday we saw areas with natural avalanche activity, and much more was likely occurring at higher elevations where we couldn’t see. Wide variation of the danger is worth mentioning. Some areas outside of Turnagain Pass in places such as Girdwood valley saw significantly more snow and rain.

AVALANCHE DISCUSSION

This storm is anCNFAIC Staff shock on an already tenuous snowpack. Over the last 4 days Turnagain pass received over 2 feet of snow at upper elevations with 2.5 inches of snow water equivalent. Most of that came in the last 2 days. Girdwood has gotten over twice that amount and Summit has only 1/3rd. Seward region also got a couple feet of snow in the mountains. Temperatures were high enough to produce rain up to 2000 feet. It looks like the peak of the storm and the peak of natural avalanche activity was yesterday, however natural avalanches are still possible today from Girdwood to Seward.

Yesterday we saw a handful of natural avalanches and heard reports of CNFAIC Staffs through the region. Since that time the storm has continued, with anCNFAIC Staff 5+ inches at higher elevations. Wind has been strong with average ridge-top winds ranging 20-40 mph. This is a perfect range to transport snow and create dangerous slabs. Near the road at Turnagain pass the snow is very wet and heavy, gradually getting softer as you climb. Since the storm began, visibility has been poor, keeping us from getting observations of the true extent of the activity.

Conditions are dangerous in the mountains today. Proper training and experience is necessary to understand where to travel safely. Staying away from upper elevations, steeper slopes, and runout paths is essential as this storm continues.

This is the 3rd storm in the last month. Both of the last 2 have added enough snow and stress to show widespread avalanche activity, breaking down to old weak layers. The instabilities lingered long after the storms ended. I expect this storm to behave the same way with human triggers possible through the weekend. The snowpack was sensitive immediately before this recent storm began and the new weight only makes things worse.

Primary concern today: New storm snow and wind slab. The recent loading will likely be the most sensitive to natural and human triggers.

Secondary concern: Old weak layers including facets, buried surface hoar, and crusts. These persistent instabilities will likely be possible to trigger many days after this storm ends.

Encyclopedia of avalanche terms.

WEATHER ROUNDUP

Over 2 feet of snow has fallen Turnagain pass during this storm. Wind has been strong with peak gusts into the 60s and averages up to the 40s. Predominant direction is from the east, which is loading West slopes and cross loading North and South facing gullies. Strong wind is expected to diminish through the day. 2-4 inches of snow is predicted to fall today with the storm dying out tonight.

ANNOUNCEMENTS

The Friends of the CNFAIC (FCNFAIC) needs your thoughts! With a new staff of forecasters and a list of previously completed goals, the program is growing and potentially heading in new directions. The FCNFAIC wants to know what you have to say about YOUR avalanche center, so please complete the following anonymous survey by February 20th. Thank you in advance for taking it!

Click here to take survey

The winner of the January drawing for Public snow and avalanche observations is Brandon Wilson! Congratulations and thanks for everyone who gave us their observations of the snowpack last month. Brandon will receive a $100 gift certificate from his choice of our sponsors. All observers are entered for the Grand Prize at the end of this season for a new Avalanche Beacon. Each quality observation submitted is good for one chance to win.

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 THU FEB 3 2011

.TODAY…CLOUDY WITH NUMEROUS SNOW SHOWERS. SNOW ACCUMULATION UP TO 2

INCHES. TEMPERATURES IN THE UPPER 20S TO LOWER 30S. SOUTH WIND 10 TO

15 MPH BECOMING VARIABLE 10 MPH IN THE AFTERNOON.

.TONIGHT…NUMEROUS SNOW SHOWERS. SNOW ACCUMULATION UP TO

2 INCHES. LOWS IN THE LOWER TO MID 20S. NORTHEAST WIND 10 TO 15 MPH.

.FRIDAY…MOSTLY CLOUDY WITH ISOLATED SNOW SHOWERS IN THE

MORNING…THEN DECREASING CLOUDS IN THE AFTERNOON. HIGHS IN THE LOWER

20S TO LOWER 30S. VARIABLE WIND 10 MPH EXCEPT NORTH 10 TO 20 MPH

NEAR SEWARD.

.FRIDAY NIGHT…MOSTLY CLEAR. PATCHY FOG. LOWS 5 TO 20

ABOVE…COOLEST INLAND. VARIABLE WIND TO 10 MPH. NEAR WHITTIER…WEST

WIND 15 TO 30 MPH.

.SATURDAY…MOSTLY SUNNY IN THE MORNING THEN BECOMING PARTLY

CLOUDY. HIGHS IN THE 20S. LIGHT WINDS EXCEPT WEST 10 TO 25 MPH

NEAR WHITTIER.

.SATURDAY NIGHT…MOSTLY CLOUDY. LOWS 15 TO 25.

.SUNDAY THROUGH WEDNESDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW.

HIGHS 25 TO 35. LOWS 15 TO 25.

TEMPERATURE / PRECIPITATION

SEWARD 38 22 32 / 60 60 20

GIRDWOOD 36 24 28 / 60 60 0

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

Temperatures dropping, currently 19 degrees. Wind picking up the last hour. Direction from the ENE.

-2600′ Seattle Ridge Wx Station-

Temperature dropping, currently 22. Wind gauge iced up.

-1800′ Center Ridge Wx Station-

Temperature 27 and falling. 4-5 inches of new snow since yesterday.