Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Saturday, January 15th 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).
We’re starting an incentive program to encourage everyone to submit snow and avalanche observations. Each quality observation will earn you one chance to win a monthly prize. At the end of this season all the submissions will go into a drawing for an avalanche beacon. Thanks for all the great work, and keep sending in those observations!
The avalanche hazard rating is MODERATE today. Human triggered avalanches are possible. If you know where to find avalanches I think you could make them happen. Overall confidence to make correct assessments is low due to poor snow structure.
The overall hazard rating is going to stay at Moderate today. The concern is that human triggered avalanches are still possible if you hit the shallow zones where you can affect the weak layers with body weight. The last storm ended more than a week ago and the likelihood of triggering avalanches continues to decline as time goes on. The structure of our December snowpack still gives us concern however and keeps our confidence of correct assessment low.
We may be entering a period of little reactivity, but with a textbook unstable layering structure. Over the last week the tracks we have seen have been relatively conservative and in alignment with what we’ve been recommending. The most recent reported avalanche was a skier triggered on Sunday 1-9 (see photo gallery). Just because we haven’t received CNFAIC Staff reports of newer avalanches doesn’t mean that you won’t find them. As people start to push out onto steeper terrain this weekend they might find the instabilities again. Current conditions make decision making difficult. A rule of avalanche science is to never trust surface hoar, or facets. We have lots of both all over the place. My honest advice is to travel with caution, don’t hang it out too far, and try to enjoy the backcountry with a healthy dose of good common sense.
The safest areas to travel this weekend are lower angle slopes. If you find yourself on steeper 35-40 degree terrain I would try to stay in deeply loaded areas where you are less likely to affect the weak layers. This is difficult to assess because the depth of the new snow is so variable due to wind loading during the last storm. Every exposed rock has a shallow zone around it and is a potential trigger point.
Think about your slope angles today. This extreme example was on Seattle ridge shortly after the storm ended. The crown broke high on the convex roll up to a slope angle of 19 degrees in this spot.
We’ve investigated a number of different avalanches since the last storm, and the common thread is that they fail on multiple different weak layers. Buried surface hoar seems to be initiating the larger avalanches, then they step down to deeper layers around the Thanksgiving rain crust.
Encyclopedia of avalanche terms.
Partly cloudy skies are expected today. Temperatures have dropped since yesterday, negative temps can be found at the valley floors and at ridge tops. The last new snow was 10 days ago. Wind has been light to moderate through the week with gusts occasionally into the 40s. Lots of people have been reporting wind affected snow and scoured areas. Weather is forecasted to remain the same for the next several days. Light to moderate wind and mostly clear skies until Wednesday.
Lisa 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 SAT JAN 15 2011
…STRONG WIND EARLY THIS EVENING THROUGH SUNDAY AFTERNOON
.TODAY…PARTLY CLOUDY. HIGHS 10 BELOW TO 5 ABOVE INLAND AND
IN THE TEENS ALONG THE COAST. LIGHT WINDS INLAND. NEAR SEWARD
AND WHITTIER…NORTH AND WEST WIND INCREASING TO 15 TO 30 MPH.
GUSTS TO 40 MPH NEAR WHITTIER IN THE AFTERNOON.
.TONIGHT AND SUNDAY…CLEAR. LOWS ZERO TO 15 BELOW INLAND AND
5 TO 10 ABOVE ALONG THE COAST. HIGHS 10 BELOW TO 5 ABOVE INLAND
AND IN THE TEENS ALONG THE COAST. NEAR WHITTIER…WEST WIND
20 TO 30 MPH WITH GUSTS TO 50 MPH. NEAR SEWARD…NORTH WIND
15 TO 30 MPH. ELSEWHERE…LIGHT WINDS.
.SUNDAY NIGHT…CLEAR. LOWS 5 BELOW TO 20 BELOW INLAND AND
SINGLE DIGITS ALONG THE COAST. NEAR SEWARD AND WHITTIER…
NORTH AND WEST WIND 15 TO 30 MPH. ELSEWHERE…LIGHT WINDS.
.MARTIN LUTHER KING JR DAY…MOSTLY SUNNY. HIGHS 10 BELOW
TO 5 ABOVE INLAND AND 15 TO 20 ALONG THE COAST. VARIABLE
WIND TO 10 MPH EXCEPT NORTH WIND 10 TO 20 MPH NEAR SEWARD.
.MONDAY NIGHT…PARTLY CLOUDY. LOWS 10 BELOW TO 5 ABOVE.
.TUESDAY…PARTLY CLOUDY. HIGHS ZERO TO 10 ABOVE.
.TUESDAY NIGHT…PARTLY CLOUDY. LOWS ZERO TO 10 ABOVE.
.WEDNESDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW SHOWERS.
HIGHS 5 TO 15 ABOVE.
.WEDNESDAY NIGHT AND THURSDAY…MOSTLY CLOUDY WITH A CHANCE
OF SNOW. LOWS 5 TO 15 ABOVE. HIGHS IN THE TEENS.
.THURSDAY NIGHT AND FRIDAY…MOSTLY CLOUDY WITH A CHANCE
OF SNOW. LOWS IN THE TEENS. HIGHS 15 TO 25.
TEMPERATURE / PRECIPITATION
SEWARD 14 7 14 / 0 0 0
GIRDWOOD 4 -6 2 / 0 0 0
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
Currently –2 degrees. Light wind with a recent gust to 28 from the ENE.
-2600′ Seattle Ridge Wx Station-
Current temperature 2. Wind in the teens from the SE.
-1800′ Center Ridge Wx Station-
Temperature 3 degrees. No new snow in the past week.