Turnagain Pass

Good morning backcountry travelers. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, March 13th 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 today is LOW. Normal caution, such as watching for old wind slabs that could knock you off your feet in steep terrain or a cornice fall, is advised. In shallow snowpacks, mainly outside the Turnagain Pass area, there is still a small chance of triggering a deeper avalanche from wind loaded steep rocky areas.

AVALANCHE DISCUSSION

LOW danger does not equal NO danger.

The main concern for today centers around normal caution in the backcounty. This includes watching for old lingering wind slabs around steep terrain that could knock a person over rocks or down an icy slope. Additionally, cornices deserve caution and are potentially more sensitive with the past week of warm temperatures; these could break farther back than expected. It is also good to keep an eye out for wet loose snow on south slopes in the afternoon, especially at lower elevations funneling into terrain traps.

It sounds like a broken record but the unlikely trigger of a slide breaking into the deeper weak layers in wind loaded steep terrain remains worthy of mention. The poor structure of weak sugary snow under a hard slab in thin snow covers (i.e., interior Kenai) has not gone away but the slab has lost much of its potential to initiate a fracture. An unlikely avalanche but can have high consequences.

The snowpack seems to have adjusted to the warm up in temperatures over the past week and is currently laying tired and dormant waiting for the next big storm. Slopes on the southern half of the compass have become especially firm with sun and wind crusts that are softening up in a few places in the afternoon. Solid refreezing overnight and cooler temperatures during the day have limited the afternoon softening the past couple days and slide-for-life conditions exist on many slopes, including the northern half of the compass on variable bullet proof windboard.

Encyclopedia of avalanche terms.

WEATHER ROUNDUP

Saturday was anCNFAIC Staff spring-like day in the backcountry. Winds were light from the east with temperatures on a slight cooling trend the past few days and reached into the upper teens to low 20’s on the ridges. Overnight temperatures dropped to the single digits below 300′ and are around the low teens above 1000′. Today expect sunny skies – again – light easterly winds and temperatures in the 20’s.

Good news: Weather models show a pattern shift that will eject the high pressure dominating the state later this coming week – stay tuned.

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 AKDT SUN MAR 13 2011

.TODAY…SUNNY. HIGHS IN THE LOWER 20S TO MID 30S. LIGHT WINDS.

NEAR SEWARD…NORTH WIND 10 MPH IN THE MORNING BECOMING LIGHT.

.TONIGHT…PARTLY CLOUDY. LOWS 5 BELOW TO 20 ABOVE…COOLEST

INLAND. NORTH TO WEST WIND 15 MPH.

.MONDAY…PARTLY CLOUDY. HIGHS IN THE LOWER 20S TO MID 30S. LIGHT

WINDS. NEAR SEWARD…NORTH WIND 10 MPH. NEAR WHITTIER…WEST WIND 15

MPH.

.MONDAY NIGHT…PARTLY CLOUDY. LOWS ZERO TO 20 ABOVE…COOLEST

INLAND. LIGHT WINDS.

.TUESDAY…MOSTLY CLOUDY. HIGHS IN THE UPPER 20S TO LOWER 40S.

LIGHT WINDS.

.TUESDAY NIGHT…PARTLY CLOUDY. LOWS 5 TO 15.

.WEDNESDAY…MOSTLY SUNNY. HIGHS 25 TO 35.

TEMPERATURE / PRECIPITATION

SEWARD 32 18 35 / 0 0 0

GIRDWOOD 29 8 26 / 0 0 0

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

10 degrees at 6am. Light wind from the East.

-2600′ Seattle Ridge Wx Station-

12 degrees at 6am. Light wind from the SE.

-1800′ Center Ridge Wx Station-

13 degrees at 6am. No new snow.