Turnagain Pass

Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Friday January 15th 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-

22-23 degrees F with light average winds 5 mph out of the E with a moderate max gust of 8-13 mph

2400′-Seattle Ridge Wx Station-

Winds have been light averaging 8 mph out of the ESE with a moderate max gust of 8-13 mph

1800′-Center Ridge Wx Station-

no new snow in 24 hours. temperatures have been between 27 and 30 deg F. Current temp is 27.

We picked up anCNFAIC Staff couple inches of snow in the last 24 hours. Only a trace last night. The radar and satellite show scattered snow showers over Prince William Sound. Short Term Weather Model Forecasts (NAM, WRF, GFS) for the Kenai Mountains near Turnagain Pass , Sea-level: GFS shows limited snow forecasted today

Forecast

WESTERN PRINCE WILLIAM SOUND-

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKST FRI JAN 15 2010

.TODAY…SCATTERED SNOW SHOWERS IN THE MORNING…THEN SNOW AND RAIN

IN THE AFTERNOON. SNOW ACCUMULATION UP TO 2 INCHES. HIGHS IN THE MID

20S TO UPPER 30S. LIGHT WINDS.

.TONIGHT…SNOW. SNOW ACCUMULATION UP TO 4 INCHES. LOWS IN THE LOWER

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

.SATURDAY…SNOW IN THE MORNING…THEN SNOW AND RAIN IN THE

AFTERNOON. SNOW ACCUMULATION UP TO 3 INCHES. HIGHS IN THE UPPER 20S

TO MID 30S. NORTHEAST WIND 10 TO 15 MPH EXCEPT NORTH 15 TO

20 MPH NEAR SEWARD.

.SATURDAY NIGHT…SNOW. LOWS IN THE 20S. VARIABLE WIND TO 10 MPH.

.SUNDAY…SNOW AND RAIN. HIGHS IN THE 30S. VARIABLE WIND TO 10 MPH.

.SUNDAY NIGHT…CLOUDY WITH SCATTERED SNOW AND RAIN SHOWERS. LOWS IN

THE 20S.

TEMPERATURE / PRECIPITATION

SEWARD 32 29 35 / 80 100 80

GIRDWOOD 30 26 30 / 40 50 60

AVALANCHE DISCUSSION

One of our observers turned in a great report of conditions yesterday from higher elevations. The skiers reported the breakable crust under light density snow up to 2600 ft. Above 3700 ft they found wind effected snow. They ski triggered a 1.5 ft deep avalanche at 3800ft were a wind slab was present. This avalanche is the first human triggered reported in nearly three weeks. This avalanche was in a tight, restricted chute were you would expect this kind of activity. These guys avoided being engulfed by the avalanche by practicing the best travel procedures available in high risk terrain. This avalanche occurred in a south west facing shoot off the Bertha Creek side of Pastoral.

I think this human triggered avalanche is the start of an unfortunate trend. We will see more activity on the crust I mentioned with additional snow load. The band of elevation I am most concerned with lies from 2000 to 3000 ft were the rain left this thin rain crust last week.

As for today, we don’t have enough snow load on this crust to elevate our avalanche hazard. We received limited snow in our advisory area yesterday and 6-10 inches in the last three days. Winds have been light to moderate.

Today’s avalanche danger will remain at LOW with pockets of MODERATE due to small wind slabs near ridgetops, and easily triggered small slabs on steep rollovers at all elevations. The hazard will increase quickly when and if heavy snow and wind materialize this weekend.

LOW is defined as: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human triggered avalanches unlikely (except glide cracks are possible). Small avalanches in isolated areas of extreme terrain.

Pockets of MODERATE is defined as heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Natural avalanches unlikely, human-triggered avalanches possible. Small avalanches in specific areas; or large avalanches in isolated areas. This moderate rating lives were the above mentioned human triggered avalanche was triggered.

A wild card right now are the glide cracks. One of these crevasse like features avalanche on Jan 4th for no obvious or apparent reason (see photo gallery). Nostradamus couldn’t have predicted that one; so, it adds to the theory that glide cracks are like cornices in that they are very difficult to predict. Sometimes they avalanche when it’s cold, sometimes when it’s warm, sometimes when it rains, sometimes when it snows, sometimes for whatever reason possible. I don’t mean to turf this avalanche problem into the unknown, but the avalanche community really does not have a good handle on what causes glide cracks to fail. We have not seen or had any reports of any more glide crack failures in the past week, but it would still be wise to avoid traveling on, near, or underneath the path of any glide cracks.

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 16th.