Turnagain Pass

Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Friday January 8th 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).

WEATHER ROUNDUP

3800′ -Sunburst Wx Station-

caput

2400′-Seattle Ridge Wx Station-

also caput

1800′-Center Ridge Wx Station-

Precip: 0.3 inches of water and 0 new snow

Total depth of 56 inches, down one from yesterday

Temperatures ranged from 33-37 degrees F current temp is 35

Only a couple of our weather stations are working this morning. Going old school with the weather forecast – if it’s raining where you are traveling it’s above freezing. If it’s snowing, you’re lucky, it’s below freezing. Current temperature in Girdwood is 30 degrees and no precip. The Turnagain Pass weather station at 1800 ft shows 35 degrees and no precip. The radar has a solid band of precipitation coming over Middleton Island heading this way. This is the leading edge of a 972 mb low that is pin wheeling into our area from the SE. The models are not showing much precip from todays weather. Expect partial clearing and cooling temperatures for tomorrow.

The rain line yesterday went as high as 2700 ft in the Girdwood Valley. The crew reported a similar rain line in Summit Lake. I will be looking at Turnagain Pass today.

Forecast

500 AM AKST FRI JAN 8 2010

.TODAY…CLOUDY. PATCHY FOG THIS MORNING. ISOLATED RAIN AND SNOW

SHOWERS THIS AFTERNOON. HIGHS IN THE UPPER 20S TO UPPER 30S. VARIABLE

WINDS 5 TO 15 MPH EXCEPT NORTH 10 TO 20 MPH NEAR SEWARD.

.TONIGHT…SNOW AND RAIN LIKELY. NO SNOW ACCUMULATION. LOWS IN THE

20S TO LOWER 30S… COLDEST INLAND. NORTH TO EAST WINDS 10 TO 25 MPH.

NORTH WINDS GUSTING TO 35 MPH NEAR SEWARD.

.SATURDAY…CLOUDY WITH A SLIGHT CHANCE OF RAIN AND SNOW. HIGHS

IN THE MID 20S TO MID 30S…COLDEST INLAND. NORTH TO EAST WINDS 10 TO

20 MPH. NORTH WINDS GUSTING TO 30 MPH NEAR SEWARD.

.SATURDAY NIGHT…MOSTLY CLOUDY IN THE EVENING THEN BECOMING

MOSTLY CLEAR. LOWS 15 TO 25. NORTHEAST WIND 10 TO 15 MPH EXCEPT

NORTH 20 TO 30 MPH NEAR SEWARD.

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

NORTHEAST WIND 10 TO 15 MPH EXCEPT NORTH 15 TO 25 MPH NEAR

SEWARD.

TEMPERATURE / PRECIPITATION

SEWARD 37 30 34 / 0 60 30

GIRDWOOD 33 25 29 / 0 0 0

AVALANCHE DISCUSSION

Today’s avalanche danger will remain at MODERATE. MODERATE is defined as: Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Natural avalanches unlikely (except glide cracks are possible) and human triggered avalanches possible. Small avalanches in specific areas; or large avalanches in isolated areas.

As the temperatures cool off the snow pack will lock up tight. The refrozen snow at lower elevations will be bomb proof and the upper snows wind slabs will mellow.

There are three main points of interest in the current snowpack.

1.Below 2200′, there is a layer buried surface hoar generally buried about 10-12 inches deep. Plus there is an ice layer/rain crust at these lower elevations. These could become a very dangerous weak layers in the future. Luckily they are confined to lower elevations.

2.Near ridgetops, we continue seeing an instability 6-12 inches deep under the surface. It only shows itself in isolated column stability tests, but it has not been reactive to skis, snowboards, or snowmachines. As of Monday 1/4/10, this layer was reported on Lipps failing with easy to moderate shears in a compression test. Plus it was observed along Seattle Ridge on Tuesday 1/5/10. One of our observers reported finding this layer on Lipps yesterday (01/07/09) again with (CT11 E Q2 (x2)) easy to moderate failures.

3.A glide crack avalanched at about 2800′ on the southern aspect of Eddies on Monday. It failed all the way to the ground and ran most of the way to the valley floor. Since this glide crack failed, we have to assume that it is possible for CNFAIC Staff glide cracks to fail. There were no obvious signs leading up to this glide crack avalanche. It is a good reminder of how unpredictable glide cracks can be. Plus, these avalanches are destructive when they fail. Avoid traveling underneath or near any glide cracks. It is very difficult to forecast when this type of avalanche occurs. They are wild cards just like cornices.

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 one will be posted tomorrow Saturday, January 9th.