Good morning backcountry travelers. This is Jon Gellings with the Chugach National Forest Avalanche Information Center on Wednesday, March 16th 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).
Today, a LOW danger of slab avalanches exists. Lingering hazards common to stable periods, such as isolated old wind slabs in extreme terrain, and weak cornices are the type of instabilities most concerning right now. Thin snowpack areas still contain an outside chance that a deeper avalanche could fail in wind loaded areas of steep slopes.
Chugach Electric Association, Inc. will be conducting patrol and maintenance of the electrical lines between Summit Lake and Turnagain Pass until April 15th. They will be operating snowmachines near the power lines between Center Ridge and Johnson Pass North T.H. under a special use permit.
Warm temperatures last night indicate that the snow surface has not gone through as hard of a freeze cycle as it could have. The Center Ridge weather station is currently at the freezing threshold, and is only going to warm up again today. These middle elevations seem to have stayed the warmest, so any wet activity today would be more likely at these elevations than at upper ones. If the sun makes it out again today, south slopes would become more concerning, with an increased possibility of producing wet snow that can be pushed down a slope.
Normal caution is advised today. The unlikely possibility exists of triggering an avalanche in steep, rocky terrain. Old wind slabs could break near rocks in these steep areas, as well as in steep cross loaded gully features. Due to the higher current temperatures, cornice failure has also become a concern of ours, so walking near cornices demands an increase in cautiousness.
We are forecasted to receive precipitation again today. Yesterday, all that we saw falling in Johnson Pass were a few snowflakes, so nothing significant at all. It looks like tonight and the near future hold a higher chance of giving us new precipitation, but I wouldn’t hold my breath for any large amount of snow with this storm.
An isolated chance still exists of any triggered avalanche breaking into our old weak snow in regions with less snow than in Turnagain Pass. Places with this concern generally have less than a 5-6 foot deep snowpack.
Encyclopedia of avalanche terms.
Winds are forecasted to get into the 20mph range, still far under what it would take to transport any amount of old snow. Temperatures are already warm at middle elevations, and they look like they could climb out of the freezing range at upper elevations. Precipitation amounts are forecasted to be pretty minimal for today, with the possibility of an increase overnight. The radar currently shows a small parcel of moist air south of Prince William Sound.
Kevin 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-
500 AM AKDT WED MAR 16 2011
.TODAY…CLOUDY WITH SCATTERED SNOW AND RAIN SHOWERS. HIGHS IN THE
30S. LIGHT WINDS EXCEPT NORTH 10 TO 15 MPH NEAR SEWARD.
.TONIGHT…SNOW LIKELY…MIXED WITH RAIN AT LOWER ELEVATIONS. SNOW
ACCUMULATION 1 TO 2 INCHES. LOWS IN THE LOWER 20S TO LOWER
30S…COOLEST INLAND. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.
.THURSDAY…SNOW AND RAIN IN THE MORNING…THEN A CHANCE OF RAIN IN
THE AFTERNOON. SNOW ACCUMULATION 1 TO 2 INCHES. HIGHS IN THE LOWER
30S TO LOWER 40S. LIGHT WINDS.
TEMPERATURE / PRECIPITATION
SEWARD 39 30 40 / 40 60 60
GIRDWOOD 35 26 39 / 30 60 80
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
23 degrees at 6am. Light wind from the NE.
-2600′ Seattle Ridge Wx Station-
28 degrees at 5am. Light wind from the NE.
-1800′ Center Ridge Wx Station-
32 degrees at 5am. No new snow.