Turnagain Pass

Good morning backcountry travelers this is Lisa Portune with the Chugach National Forest Avalanche Information Center on Monday, January 3rd 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 the avalanche hazard has increased to HIGH on all windloaded slopes greater than 30 degrees. Non wind-affected slopes and rain-saturated terrain at the lower elevations will have a CONSIDERABLE danger today. Large natural and human-triggered avalanches are likely! 9-18 inches of new snow, hurricane-force winds, and heavy rain at the lower elevations equals dangerous avalanche conditions. Today is not the day to be in the mountains.

AVALANCHE DISCUSSION

Today’s advisory is pretty straightforward…stay out of avalanche terrain. It’s a skull and crossbones kind of day. Natural avalanches are most likely happening as I write this morning. The NWS has forecasted up to 10 inches of additional snow today at the higher elevations along with continued hurricane-force winds out of the east. Winds on Sunburst hit 104mph at 6am this morning.

Yesterday Jon and his partner intentionally triggered a 60 ft. wide windslab on a small test slope at 2000 feet that stepped down to several different layers of buried surface hoar as well as the Thanksgiving Rain Crust (TRC) three feet down. It looks like we have hit the tipping point. All of the heavy dense snow from the last five days (20”+) fell on a very weak upper snowpack littered with multiple layers of buried surface hoar, weak faceted snow, and the TRC. Any avalanches triggered today have the potential to step down to these deeper weak layers, creating a much larger avalanche than anticipated.

Keep in mind that whenever the weather happens to mellow out, natural avalanches will subside but most steep slopes at the mid and upper elevations will be hair-trigger for the following 24 hours.

Here’s a shout out to the Skustads who have finally settled into their new place in Ely, MN. It’s raining sideways and Girdwood is an ice rink! We miss you guys!

Encyclopedia of terms: www.fsavalanche.org/Encyclopedia.aspx

WEATHER ROUNDUP

Nine inches of new snow fell in the last 24 hours in Turnagain Pass with probably twice as much at the higher elevations. That brings our snowfall total for the last five days to 21 inches of new snow (1.7” water) at 1800 feet elevation. The winds have been steadily ramping up since 10am yesterday morning and are now averaging 60-70mph out of the east with gusts to 104. Mountain temps have remained steady in the mid 20’s to low 30’s the last few days with rain generally below 1500 feet. Expect rain below 1000 feet today, hurricane-force easterly winds, and up to 10 inches of new snow at the higher elevations.

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:

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKST MON JAN 3 2011

…HIGH WIND WARNING IN EFFECT UNTIL MIDNIGHT AKST TONIGHT FOR

PORTAGE VALLEY AND TURNAGAIN ARM…

.TODAY…RAIN…MIXED WITH SNOW AT TIMES INLAND. PRECIPITATION MAY BE

HEAVY AT TIMES. SNOW ACCUMULATION UP TO 4 INCHES NEAR TURNAGAIN PASS.

HIGHS IN THE LOWER 30S TO LOWER 40S. EAST WIND 10 TO 20 MPH EXCEPT 30

TO 45 MPH WITH GUSTS TO 75 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN

ARM.

.TONIGHT…RAIN…MIXED WITH SNOW AT TIMES INLAND. SNOW ACCUMULATION

UP TO 3 INCHES NEAR TURNAGAIN PASS. LOWS IN THE UPPER 20S TO MID 30S.

EAST WIND 10 TO 20 MPH. THROUGH PORTAGE VALLEY AND TURNAGAIN ARM…

EAST WIND 35 TO 50 MPH WITH GUSTS TO 75 MPH DECREASING TO 20 TO 35

MPH AFTER MIDNIGHT.

.TUESDAY…SNOW AND RAIN. SNOW ACCUMULATION UP TO 2 INCHES INLAND.

HIGHS IN THE 30S. SOUTHEAST WIND 10 TO 20 MPH EXCEPT EAST 20 TO 35

MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.

TEMPERATURE / PRECIPITATION

SEWARD 39 35 38 / 100 100 100

GIRDWOOD 39 35 37 / 100 100 100

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

Winds have been steadily ramping up since 10am yesterday morning and are now averaging 60mph out of the northeast with gusts to 104. Temps yesterday ranged from 25F to 26F. The current temp is 25F.

-2600′ Seattle Ridge Wx Station-

stopped recording wind speeds yesterday morning. Temps yesterday ranged from 27F to 29F. The current temp is 27F.

-1800′ Center Ridge Wx Station-

recorded 9 inches of new snow and 0.7” of water in the last 24 hours. Temps yesterday ranged from 32F to 34F. The current temp is 31F with a total snowpack depth of 63 inches.