Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Saturday, January 2nd 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).
All areas designated for snowmachines on the Chugach National Forest are open to snowmachines except Placer and 20 Mile. Please remember that Center and Divide Creeks near the Johnson Pass North Trailhead are always closed due to the current Forest Plan.
3800′ -Sunburst Wx Station-
11 deg F, winds are averaging 12-18 with gusts of 19-23 out of the E
3400′ –Fresno Ridge Wx Station-
11 deg F, winds are averaging 5 with gusts of 10-14 out of the SSE
2400′-Seattle Ridge Wx Station-
winds are averaging 12-14 with gusts to 16 out of the SE
1800′-Center Ridge Wx Station-
Precip: 0.0 inches of water
Total depth of 59 inches after 1″ of settlement
12 deg F
Precip: 0. 0 inches of water
Total depth of 30 inches, -7.6 deg F
WESTERN PRINCE WILLIAM SOUND-
500 AM AKST SAT JAN 2 2010
.TODAY…INCREASING CLOUDS IN THE MORNING. SNOW LIKELY BY AFTERNOON.
SNOW ACCUMULATION 1 TO 2 INCHES. HIGHS IN THE MID TEENS TO UPPER
20S…COLDEST INLAND. LIGHT WINDS EXCEPT NORTH 15 TO 25 MPH NEAR
.TONIGHT…SNOW. SNOW ACCUMULATION UP TO 3 INCHES. LOWS ZERO TO 20
ABOVE…COLDEST INLAND. LIGHT WINDS EXCEPT NORTH 15 TO 25 MPH NEAR
.SUNDAY…NUMEROUS SNOW SHOWERS. SNOW ACCUMULATION UP TO 2 INCHES.
HIGHS IN THE 20S. VARIABLE WIND 10 MPH EXCEPT NORTH 10 TO 20 MPH
.SUNDAY NIGHT…SNOW. LOWS 10 TO 20 ABOVE. VARIABLE WIND 10 MPH
EXCEPT EAST 10 TO 25 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN
.MONDAY…SNOW AND RAIN LIKELY. HIGHS IN THE UPPER 20S TO MID
30S. EAST WIND 15 TO 20 MPH EXCEPT EAST 20 TO 35 MPH THROUGH
PORTAGE VALLEY AND TURNAGAIN ARM.
.MONDAY NIGHT…RAIN AND SNOW LIKELY. LOWS 15 TO 25.
TEMPERATURE / PRECIPITATION
SEWARD 28 10 28 / 70 70 60
GIRDWOOD 15 11 28 / 60 80 50
The winds are starting to pick up around the advisory area with ridgetop gusts to 23 out of the east. A slight inversion still exists in the Girdwood Valley and Summit Lake. Summit is the coldest at -7.6 deg F. Fog persisted yesterday below 1200 feet, expect this to mix out as low pressure and precip move into the area this afternoon. The radar and satellite currently show clear skies, with snow showers building in Prince William Sound. Multiple lows are stacked up to the south and southwest. Expect a change in the weather pattern with warmer temperatures and an increased chance of snow.
One more day of limited weather and no natural or human triggered avalanches in the last week will allow our avalanche hazard to remain at LOW today. LOW is defined as: Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Natural and human-triggered avalanches unlikely. Small avalanches in isolated areas or extreme terrain. Terrain features to be mindful of include steep rollovers (>38 %) near ridgetops and hanging snowfields that look wind loaded.
Depending on the timing of this afternoon’s snow fall and the amount, the chance of small avalanche activity will increase with new snow and wind.
On New Years Eve we found two layers of interest at 8 and 10 inches below the snows surface. Both of these layers failed easily in stability tests (CT 6 and CT 11 Q2). These layers looked to be mid storm interfaces and should heal over time. The surface snow ranged from surface hoar to surface faceting. Death crust below 2000 ft and fairly good snow above. I have also noticed that cornices are getting quite large in size and that large chunks have been breaking off. Mostly triggered by humans. Make sure you give them lots of space. A great picture of a cornice break exists in our photo gallery.
AnCNFAIC Staff concern today will be the glide cracks. A couple of large glide cracks have opened north of the snowmachine up track to Seattle ridge. Odds are there are numerous more of these crevasse like features which may be difficult to see. People and dogs have fallen into these cracks before, and they can be very difficult to get out of. Sometimes these glide cracks will avalanche, but this does not appear to be a concern today. It’s always a good idea to treat glide cracks like cornices and avoid traveling underneath their path. Like cornices, glide cracks are very difficult to predict.
Always remember that safe backcountry travel requires training and experience. You control your own risk by choosing where, when, and how you travel.
If you get out in the backcountry give us a call or email us with your snow and avalanche observations. Thanks for checking today’s avalanche advisory and have a great day.