Turnagain Pass

Good morning backcountry travelers this is Lisa Portune with the Chugach National Forest Avalanche Information Center on Monday, November 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).

ANNOUNCEMENTS

All areas designated for snowmachines are still closed. We are measuring the snow in these areas daily and will open them as soon as there is enough snow to protect the ground and vegetation from being torn up by the tracks of a snowmachine. Thanks for your patience.

WEATHER ROUNDUP

No new snow fell in the last 48 hours in Turnagain Pass. Ridgetop winds were light yesterday, averaging 5mph out of the northwest, while mountain temperatures ranged from the low 30’s at the middle elevations to the low 20’s at the upper elevations. A trace of new snow fell in Girdwood last night, but skies are clear as of 4am this morning. Ridgetop winds are currently light out of the west while temperatures this morning range from 18F@3800′ to 20F@1800′ to 27F@sealevel. Cold air will spill over the Alaska Range and into southcentral today as a blocking ridge of high pressure moves over the mainland. Mountain temperatures will continue to drop throughout the day and hit the single digits by this evening while ridgetop winds will increase this afternoon and average15-25mph out of the northwest. Expect sunny skies through the week.

AVALANCHE DISCUSSION

Today the avalanche danger remains at LOW overall with areas of MODERATE hazard underneath glide cracks and on steep windloaded terrain near ridgetops. Lingering pockets of sensitive windslab may exist at the higher elevations above 3000 feet, so use extra caution before dropping in to steep lines. Two days ago a skier triggered an avalanche on Superbowl Peak that broke 1-2 feet deep and 60-80 feet wide on recently formed windslab. By late this afternoon, it may be possible to trigger shallow soft slabs on steep slopes if the north winds become strong enough to move snow. Watch for crossloading down low off the ridgelines where the snow is softer and more transportable. Wind-driven snow will increase the avalanche hazard to MODERATE overall.

I would expect that the current surface windslab has lost most of its energy and is less sensitive to human triggering, but there could be a few pockets of lingering instability at elevations above 3000 feet where colder temperatures keep instabilities around longer. New windslabs will be our main concern later today. We can only hope that the north winds don’t hammer our snowpack too much this week. As far as recent natural avalanches, glide cracks have been avalanching pretty much every day for the past week. This is certainly a banner year for these full-depth cracks in the snowpack. Make sure you don’t find yourself inadvertently below one of these things and in the line of fire.

Kevin 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 NOV 15 2010

…STRONG WIND THIS AFTERNOON THROUGH LATE TUESDAY NIGHT NEAR

SEWARD AND WHITTIER…

.TODAY…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS IN THE

MORNING…THEN PARTLY CLOUDY IN THE AFTERNOON. HIGHS IN THE UPPER

20S TO MID 30S. VARIABLE WIND 10 MPH. NEAR WHITTIER…WEST WIND

INCREASING TO 30 TO 45 MPH BY AFTERNOON. NEAR SEWARD…NORTH WIND 15

MPH INCREASING TO 30 TO 45 MPH IN THE AFTERNOON.

.TONIGHT…PARTLY CLOUDY. LOWS 10 TO 20 ABOVE…COOLEST INLAND.

NORTHWEST WIND 10 TO 20 MPH. NEAR SEWARD…NORTH WIND 30 TO 45 MPH.

NEAR WHITTIER…WEST WIND TO 35 TO 50 MPH.

.TUESDAY…MOSTLY SUNNY. HIGHS IN THE 20S. NORTH WIND 10 TO 20 MPH.

NEAR SEWARD…NORTH WIND 30 TO 45 MPH. NEAR WHITTIER…WEST WIND TO

35 TO 50 MPH.

TEMPERATURE / PRECIPITATION

SEWARD 33 22 28 / 30 0 0

GIRDWOOD 28 9 23 / 30 0 0

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

recorded light westerly winds yesterday averaging 5mph. The high temp yesterday was 23F. The current temp is 18F with light and variable winds.

-2600′ Seattle Ridge Wx Station-

recorded light westerly winds yesterday averaging 5-10mph. The high temp yesterday was 26F. The current temp is 20F with winds averaging 5mph out of the west.

-1800′ Center Ridge Wx Station-

recorded no new snow in the last 24 hours. The high temp yesterday was 32F at noon. The current temp is 22F with a total snowpack depth of 50 inches (minus 1 inch due to settlement in the last 24 hours). 113″ inches of snow fell from Nov. 1-12.