Turnagain Pass

Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Friday January 29 at 7 am. 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

!FREE! Avalanche Education in Anchorage this weekend from Alaska Avalanche School.

Avalanche Awareness Lecture Series

(No Registration Required)

WHEN: Saturday Jan. 30, 2010

Time: Seating and sign in begins at 8:45am. Lecture runs from 9:00am to 1:00pm

WHERE: Alaska Pacific University Carr-Gottstein Building, Room 102

4101 University Drive Anchorage AK

DURATION: The Lecture has a run time of 4 Hours

with intermittent breaks throughout.

COST: FREE!!

Avalanche Field Workshop

(Registration is Required: Please Contact the Office to Enroll)

By Popular Demand there are 2 Avalanche Field Workshops

WHEN:Morning Program: Sunday, January 31, 2010: 9:00 am to 1:00 pm

Afternoon Program: Sunday, January 31, 2010: 1:30 pm to 5:30 pm

WHERE:Glen Alps Trail Head (Flat Top Parking Lot)

Chugach State Park

DURATION:Each program will run 4 hours. Please be ready to spend the duration of the program outside.

COST:FREE

WEATHER ROUNDUP

3800′ -Sunburst Wx Station-

Current temp is 26 (2 degrees warmer than yesterday). Winds are 17 mph with gust of 28-39 out of the southeast.

2400′-Seattle Ridge Wx Station-

Winds are blowing 16 mph with gusts of 28-39 out of the east

1800′-Center Ridge Wx Station-

Current temp is 32 (2 degrees warmer than yesterday) .2 inches of water equivalent and one ince of new snow.

Parking Lot Snow Stake Measurements (taken 2pm 1/27/2010)

Eddies Lot: 1” new snow

Motorized Lot: 2” new snow

Sunburst Lot: 1” new snow

Johnson Pass North Lot: .5” new snow

Temps are warmer again this morning at all wx stations from sea-level to the ridgetops ranging from 35 degrees F at sea level to 26 degrees F at 3800′. Winds are still moderate averaging in the teens with strong gusts in the 30mph range on most ridgetop wx stations this morning. The Middleton radar shows moderate precip moving northwest over PWS toward us. The Kenai radar shows light precip over Turnagain Pass. The models jive with the NWS this morning with .1-.25 inches of water making it’s way over the coastal mountains into our area. More precip for Whittier and Seward.

Forecast (National Weather Service)

WESTERN PRINCE WILLIAM SOUND-

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKST FRI JAN 29 2010

.TODAY…SNOW AND RAIN LIKELY IN THE MORNING…THEN A CHANCE OF

RAIN AND SNOW IN THE AFTERNOON. NO SNOW ACCUMULATION. HIGHS IN

THE MID 30S TO LOWER 40S. EAST WIND 10 TO 20 MPH EXCEPT EAST

15 TO 30 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.

.TONIGHT…MOSTLY CLOUDY. LOWS IN THE LOWER 20S TO LOWER 30S.

LIGHT WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.

.SATURDAY…MOSTLY CLOUDY. HIGHS IN THE 30S. LIGHT WINDS EXCEPT

NORTH 10 MPH NEAR SEWARD.

.SATURDAY NIGHT…MOSTLY CLOUDY IN THE EVENING THEN BECOMING

PARTLY CLOUDY. LOWS IN THE LOWER 20S TO LOWER 30S. LIGHT WINDS

EXCEPT NORTH 10 MPH NEAR SEWARD.

.SUNDAY…PARTLY CLOUDY. HIGHS IN THE LOWER TO MID 30S. LIGHT

WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.

TEMPERATURE / PRECIPITATION

SEWARD 38 26 36 / 70 0 0

GIRDWOOD 38 27 36 / 50 0 0

AVALANCHE DISCUSSION

Today’s avalanche hazard will remain at MODERATE. The current weather system is not packing to much punch but is adding incremental weight thus stress to our snowpack. I believe our current weak layers can handle this added stress in most areas. Areas of concern lie near ridge tops where 20-40 mph winds have created wind slabs in deposition areas.

Yesterday we found limited new snow over the advisory area and little change in snow stability scores on Sunburst Mountain in T-Pass. With only one to two inches of new snow and strong winds we found 3 inch wind slabs in the alpine. This wind slab had moderate energy with shooting cracks only propagating below the ski.

Take time to recap our weak layers and draw a mental picture for future reference. We just buried big surface hoar under 2-3 inches snow. This is your upper most layer of concern and the one you will see reactive today. The next layer down is a rain crust that has a whole gamet of snow crystal types associated with it. That layer is about 2 feet deep. Below that at lower elevations you could still see some buried surface hoar. Most of these layers are found between 1000 and 3000 ft.

The layer of most concern to me is the rain crust 2 feet deep from 2000 to 3000 ft. This layer should have tightened up over the last 2 weeks but it really didn’t. We continue to see moderate to hard failures on this layer. This area of weakness has all the ingredients of an avalanche, a bed surface crust, a weak layer and a 2 plus foot slab on top of it. We all need to keep an eye on this layer.

A secondary concern continues to exists below 2000′ on facets and surface hoar near the rain crust. This lower elevation problem layer is still showing signs of instability. Observations of a large whoomph or collapse in the trees near Tincan on Sunday 1/24/2010 indicate lingering weak layers at lower elevations. This lower elevation weak layer could become a serious problem, especially after the next storm, in places like Placer Valley, Kern Creek, Peterson Creek, or Girdwood Valley where steep slopes exist near sea level.

Always remember that safe backcountry travel requires training and experience. You control your own risk by choosing where, when, and how you travel.

Thanks for checking today’s avalanche advisory. The next advisory will be posted tomorrow Saturday January 30th.