Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Sunday, January 30th 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).
The Friends of the CNFAIC (FCNFAIC) needs your thoughts! With a new staff of forecasters and a list of previously completed goals, the program is growing and potentially heading in new directions. The FCNFAIC wants to know what you have to say about YOUR avalanche center, so please complete the following anonymous survey by February 20th. All information gathered will be discarded after that time. You do not need to answer all the questions, but the more complete the survey is, the better the data will be. This survey will be located here for a week, and will then be relocated to the bottom of the advisory for the remainder of the open period. Thank you in advance for taking it!
Click here to take survey
The avalanche hazard is MODERATE but further explanation is needed to fully understand the hazard. I wish I could bump it up to pockets of CONSIDERABLE based on lots of recent human triggered avalanches, but we aren’t seeing naturals. We are back to describing it as scary MODERATE. With lots of weekend traffic yesterday we received many reports of UNSTABLE conditions including a very close call near Summit Lake that required a complex rescue operation.
The incident in Summit yesterday is worth talking about as a sobering reminder of current conditions. Four skiers triggered an avalanche on Butch mountain that broke well above them as they were ascending on skins. All four were caught and carried through trees. At least one was buried completely and rescued with an avalanche beacon. Injuries include broken bones and possible internal injuries. The avalanche was 300-400 feet wide, 1-3 feet deep, and dropped about 800 vertical feet. Thanks to numerous agencies and volunteers involved in the rescue efforts, which supported a positive final outcome.
CNFAIC Staff events of the last 2 days: A skier triggered on Goldpan/Superbowl/Bertha Creek (see photo), a snowmachine triggered in Main Bowl, a skier triggered on Seattle ridge across from Magnum (reported as up to 8 feet deep), a snowmachine triggered in Carter lake with significant damage to the sled. Also the full burial in Lost Lake on Monday. That brings the total this week to 9 people reportedly triggering or caught in avalanches.
Based on these recent events my own caution level is rising. Conditions are unpredictable enough that we can’t show definitive patterns to the incidents. The snowpack is tricky and beyond our ability to make correct decisions in steeper terrain. In consequential terrain your ability to stay safe comes down to a roll of the dice. The only way to increase your chances is to hedge your bets by following strict safe travel protocols or choose safer lines. I noticed a lot of people yesterday riding open slopes 2 or more at a time and riding above people ascending below them. This is a great way to cause multiple burials.
Our basic snowpack structure is staying the same and it’s causing persistent instabilities. Multiple layers of facets, buried surface hoar, and crusts are directly causing the avalanche incidents. Depending on where you go it could be any or all of these layers contributing to the problem. Yesterday some snowpit data was showing clean, energetic shears and full propagation in extended column tests. CNFAIC Staff pits nearby had hard, poor quality failures. The distribution of the weak layers is becoming impossible to track.
The distribution of the recent surface hoar could make lower elevation steep slopes surprisingly dangerous. Most people are not traveling in this more heavily treed terrain, but it could produce some big surprises. We have several recent reports of massive sphincter clenching whoomphs in the trees. This was predictable from the presence of abnormally large surface hoar. If you find that collapse on a slope it could easily avalanche. This is what happened last year in the Grandview snowmachine fatalities. They triggered a low elevation slope above them in treed terrain with buried surface hoar as the weak layer.
Encyclopedia of avalanche terms.
The most recent snowfall ended on the 25th. Wind that started 2 nights ago has been blowing significantly and is contributing to the current problems. Lots of wind loading was seen yesterday. Predominant direction is from the east, which is loading West slopes and cross loading North and South facing gullies. Strong wind is expected to continue today. A chance of snow is increasing today and tonight.
Jon 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 AKST SUN JAN 30 2011
…STRONG WIND THIS EVENING THROUGH MONDAY MORNING THROUGH PORTAGE
VALLEY AND ALONG TURNAGAIN ARM…
.TODAY…MOSTLY CLOUDY. ISOLATED SNOW SHOWERS IN THE AFTERNOON. HIGHS
IN THE MID 30S TO LOWER 40S. EAST WIND 10 TO 20 MPH EXCEPT EAST WIND
30 TO 45 MPH THROUGH PORTAGE VALLEY AND ALONG TURNAGAIN ARM.
.TONIGHT…SNOW LIKELY. AREAS OF BLOWING SNOW. SNOW ACCUMULATION UP
TO 3 INCHES. LOWS IN THE UPPER 20S TO LOWER 30S. EAST WIND 10 TO 20
MPH EXCEPT EAST WIND 30 TO 45 MPH THROUGH PORTAGE VALLEY AND ALONG
.MONDAY…SNOW LIKELY. AREAS OF BLOWING SNOW. SNOW ACCUMULATION UP
TO 4 INCHES. HIGHS IN THE UPPER 20S TO UPPER 30S. NORTHEAST WIND 15
TO 30 MPH EXCEPT EAST 35 TO 50 MPH THROUGH PORTAGE VALLEY AND
.MONDAY NIGHT…SNOW. LOWS IN THE MID 20S TO MID 30S. EAST WIND
15 TO 30 MPH.
.TUESDAY…RAIN AND SNOW LIKELY. HIGHS IN THE 30S TO LOWER 40S. EAST
WIND 10 TO 25 MPH.
.TUESDAY NIGHT…SNOW LIKELY. LOWS 25 TO 35.
.WEDNESDAY…SNOW AND RAIN LIKELY. HIGHS IN THE 30S.
.WEDNESDAY NIGHT AND THURSDAY…SNOW LIKELY. LOWS IN THE 20S.
HIGHS 25 TO 35.
.THURSDAY NIGHT…MOSTLY CLOUDY. LOWS 15 TO 25.
.FRIDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW. HIGHS IN THE 20S.
.FRIDAY NIGHT AND SATURDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW.
LOWS 15 TO 25. HIGHS IN THE 20S.
TEMPERATURE / PRECIPITATION
SEWARD 35 30 36 / 80 90 80
GIRDWOOD 34 28 36 / 30 60 60
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
Temperatures 20 degrees. Wind gusting to 60 from the ENE.
-2600′ Seattle Ridge Wx Station-
Temperature 24 degrees. Wind gusting to 55 from the SE.
-1800′ Center Ridge Wx Station-
Temperature 29. No new snow. One inch of settlement since yesterday.