Turnagain Pass

Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Saturday, February 26th 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).

BOTTOM LINE

Today’s avalanche danger rating is MODERATE. Very specific wind loaded areas will have a CONSIDERABLE danger with heightened avalanche hazard on the lee sides of ridges. Deep slab concerns are focused in shallow snowpack zones and specific shallower points in steeper terrain.

AVALANCHE DISCUSSION

Yesterday’s storm brought no significant snow to Turnagain Pass. Wind however was strong through the region and that trend continues today. Gusts have been measured as high as 89mph on Seattle ridge. Wind loading was very obvious yesterday and speeds accelerated overnight. Observations show that East, North, and South aspects are the dominant lee sides depending on location. Human triggered avalanches in the currently wind loading steep terrain are likely today.

Check out this photo from yesterday showing the scouring effects of recent wind on windward slopes.

It’s now been 2 1/2 weeks since the last confirmed deep slab avalanche in Turnagain Pass. More recent deep avalanches have happened in shallower and weaker areas including Raggedtop and Summit. The general trend has been for these weaknesses to slowly become more difficult to trigger. Right now they seem to be quite stubborn, but could reawaken with a big storm load in the future. Likely trigger points include areas where you could affect the weak layer in shallow spots. Traveling in shallow areas like Summit deserves a completely different level of caution than Turnagain Pass. See the Summit advisory today for a discussion of those concerns and recent observations.

WEATHER ROUNDUP

Strong wind yesterday continues through today. A high wind warning is in effect near Whittier. Turnagain arm is channeling a west wind with gusts recorded into the 80s overnight. Weather stations are showing West or Northwest wind through Turnagain and Southwest around Summit. Temperatures dropped fast yesterday going from 32 to 0 currently at the ridgetops. Today clear skies, strong wind, and cold temperatures are expected.

ANNOUNCEMENTS An APU student is conducting a survey on backcountry skiing group dynamics. Click on the link to participate in research on avalanche safety. Click here to take survey

The Forest Service is installing winter use bridges across Granite creek in Turnagain Pass. Be aware of an ice road from the Lyon creek bridge south towards Johnson Pass on the West side of the highway. Heavy equipment will also be used in the area.

Wendy 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-

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKST SAT FEB 26 2011

…HIGH WIND WARNING IN EFFECT UNTIL 6 AM AKST SUNDAY NEAR

WHITTIER…

.TODAY…PARTLY CLOUDY. HIGHS 15 TO 25. NORTHWEST WIND 15 TO 30 MPH

EXCEPT WEST WIND 40 TO 55 MPH WITH GUSTS TO 75 MPH NEAR WHITTIER.

NEAR SEWARD…NORTH 30 TO 45 MPH.

.TONIGHT…CLEAR. LOWS 10 BELOW TO 15 ABOVE…COOLEST INLAND.

NORTHWEST WIND 10 TO 25 MPH EXCEPT WEST WIND 40 TO 55 MPH WITH GUSTS

TO 75 MPH NEAR WHITTIER. NEAR SEWARD…NORTH 35 TO 50 MPH.

.SUNDAY…SUNNY. HIGHS 15 TO 20. NORTHWEST WIND 10 TO 25 MPH EXCEPT

WEST WIND 30 TO 45 MPH WITH GUSTS TO 60 MPH NEAR WHITTIER. NEAR

SEWARD…NORTH WIND 30 TO 45 MPH.

.SUNDAY NIGHT…CLEAR. LOWS 5 BELOW TO 15 ABOVE…COOLEST INLAND.

NORTHWEST WIND 10 TO 25 MPH EXCEPT NORTH 25 TO 40 MPH NEAR

SEWARD. NEAR WHITTIER…WEST WIND 25 TO 40 MPH WITH GUSTS TO 55 MPH.

.MONDAY…SUNNY. HIGHS IN THE 20S. NORTHWEST WIND 10 TO 20 MPH

EXCEPT NORTH 20 TO 35 MPH NEAR SEWARD.

TEMPERATURE / PRECIPITATION

SEWARD 27 15 20 / 0 0 0

GIRDWOOD 21 6 18 / 0 0 0

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

Temperature 0 degrees. Strong wind from the NW, gusting to 48.

-2600′ Seattle Ridge Wx Station-

Temperature 5 degrees. Strongest recorded wind in the region with sustained wind in the 40s and max gust to 89 overnight from the West.

-1800′ Center Ridge Wx Station-

Temperature 11 degrees. No new snow recorded.