Turnagain Pass

Good morning backcountry travelers. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, March 6th 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

The avalanche danger is mostly LOW. There are pockets of MODERATE danger for triggering an avalanche that breaks into the deeper weak layers mainly associated with overlying wind slabs. These pockets can be found on wind loaded slopes with rollovers, rocky features, gullies, and shallow snowpack areas.

AVALANCHE DISCUSSION

It was good to see some snow showers in the mountains yesterday, but the trace that fell was just enough to cover a few pine needles. It appears the snow conditions remain prime for anCNFAIC Staff day of watching the Iditarod or finishing those taxes.

It seems like old news, but the biggest concern remains for an avalanche that fails in the deeper weak faceted snow. There have been no signs of these weak layers strengthening. The likelihood of triggering an avalanche has decreased but the chances that the slide will be unmanageable remain. Most of the avalanches we investigated this past week, after the wind storms, broke in these deeper weak layers underneath a wind slab. Most suspect slopes are areas where old wind slabs overlie either the original slab or the weak faceted snow itself. These are likely found in areas with older wind loading on steep rollovers and gullies, unsupported slopes and snowpacks less than 5-6 feet deep.

With the ramp up in winds yesterday and overnight there is a possibility of new wind drifts today. These are likely to be minor with the limited snow available for transport. Most wind slabs out there are several days old, very stubborn and hard to trigger, but worth keeping in mind. In many areas they lie on top of weak faceted snow making them slower to heal, especially with our recent cold temperatures. Watch for areas with wind loading on convexities, steep rocky terrain and in cross loaded slopes and gullies.

WEATHER ROUNDUP

The good news is we finally saw some clouds and flurries yesterday. The bad news is it was short lived with only a trace accumulating. The winds picked up yesterday from the east, gusting up to 40mph and temperatures warmed into the 30’s. Overnight temperatures remained in the 20’s and the wind backed off with gusts near 30mph. Today temperatures will again be in the 30’s with light winds gusting from the east in the 20’s on the ridgelines. Skies should be mostly to partly cloudy as the low pressure in the Gulf of Alaska pushes clouds over our region.

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.

I 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 SUN MAR 6 2011

.TODAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW…MAINLY SOUTH OF MOOSE

PASS. HIGHS IN THE MID TO UPPER 30S. VARIABLE WIND 10 MPH EXCEPT

NORTH 10 TO 20 MPH NEAR SEWARD.

.TONIGHT…MOSTLY CLOUDY. A SLIGHT CHANCE OF SNOW…MAINLY SOUTH OF

MOOSE PASS. LOWS 10 TO 25 ABOVE…COOLEST INLAND. NORTHEAST WIND

5 TO 10 MPH EXCEPT NORTH 10 TO 20 MPH NEAR SEWARD.

.MONDAY…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS…MAINLY SOUTH OF

MOOSE PASS. HIGHS IN THE 30S. NORTHEAST WIND 15 MPH.

.MONDAY NIGHT…MOSTLY CLOUDY IN THE EVENING THEN BECOMING PARTLY

CLOUDY. LOWS 15 TO 25…COOLEST INLAND. LIGHT WINDS EXCEPT NORTH

10 MPH NEAR SEWARD.

.TUESDAY…PARTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS IN

THE 30S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.

TEMPERATURE / PRECIPITATION

SEWARD 38 26 37 / 20 20 40

GIRDWOOD 33 20 33 / 0 0 0

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

Temperature 22 degrees. Upper teens from the NE gusting into the upper 20’s.

-2600′ Seattle Ridge Wx Station-

Temperature 27 degrees. Light winds from the SE gusting into the mid-teens.

-1800′ Center Ridge Wx Station-

Temperature 27 degrees. No new snow.