Turnagain Pass Avalanche Forecast

GENERAL ANNOUNCEMENTS

Good Morning backcountry travelers, this is Matt Murphy with the Chugach National Forest Avalanche Information Center on Thursday, January 8, 2009 at 7am. This will serve as a general backcountry avalanche advisory issued 5 days a week Wednesday-Sunday for the Turnagain Arm (Turnagain Pass is the core advisory area). Local variations always occur.

There have been reports of skiers and snowmachiners getting deep frost bite on their toes and faces over the past couple days. Please be careful with these super cold temps.

We would like to give a huge THANK YOU to the latest batch of CNFAIC Observers, Blaine and Nancy from the Alaska Avalanche School, and the Friends of the CNFAIC for a great weekend of avalanche observer training. Braving the freezing cold temps really shows your commitment to the local mountain community. We look forward to your future observations. Thanks again.

MOUNTAIN WEATHER ROUND UP

In the last 24 hours…

-The Center Ridge weather station at 1800 feet in Turnagain Pass-

No data.

-The Grandview weather station at 1100 feet along the railroad tracks-

Recorded 0.1 inches of water and 0 inches of new snow. Current temp is -8 degrees F (6 degrees warmer than yesterday)

-Sunburst weather station at 3800 feet in Turnagain Pass-

Recorded calm to light winds averaging 1-9mph from the ENE with light gusts to 16 mph. Current temperature is 5 degrees F (3 degrees warmer then yesterday)

-Surface Analysis Maps-

From 3 am Wednesday to 9pm last night…

Show a very weak low pressure just SE of Prince William Sound. These maps also show that the storm south of the Aluetians has maintained its strenght as is slowly moving in a NE direction.

-Jet Stream-

The analysis from 9pm last night still shows the main flow is to our south flowing west-east towards Washington. The forecast continues to show a change in this pattern on Saturday night or Sunday when it is predicted to shift and flow south to north from Hawaii toward us.

-Satellite-

As of 5:30 am this morning…Shows that it is pretty calm above us. You can also see that storm south of the Aluetians is pulling up quite a bit of moisture from the south.

-Radar-

The Middleton radar actually shows a small wall of light-moderate precip south of Prince William Sound. The Kenai radar shows does not show very much.

-General Weather Observations-

Compared to yesterday…Temps are warmer at all weather stations by 3-10 degrees. There is still a temperature inversion where temps have made it above zero on the ridges but remain below zero in valley bottoms. Its still cold out there. Portage is negative 19 and Girdwood Valley is negative 7. Ridgetop winds have been very calm to light.

PRIMARY AVALANCHE CONCERNS

-Faceted surface snow

-Surface Hoar

SECONDARY AVALANCHE CONCERNS

-Glide Cracks (see photos)

-Small and shallow wind slabs near ridges

-October facets

WATCH OUT SITUATIONS

-The next storm or wind event

AVALANCHE AND SNOWPACK DISCUSSION

No change from yesterday. Let’s keep an eye on the NOAA weather forecasts and be ready when the next storm hits us, because the avalanche hazard will increase whenever that happens.

Future issues:

We have a grab bag of weak layers near the surface that WILL become a problem when the next big storm comes in….

-This cold weather has created a bad temperature gradient in the top 1-2 feet (~40cm) of snow. Recent snow temperatures taken on Sunburst, Main Bowl, Magnum, and Lipps show conditions favorable for the formation of facets. Plus, we have confirmed these facets through our magnifying glasses in the surface snow. Basically, this means that a bad weak layer is forming in the current surface snow. This weak layer is everywhere. That means all aspects and elevations.

-The recent clear weather, calm winds and cold temps have created surface hoar from the highway to the ridgetops in certain areas. The biggest surface hoar is found at low to mid elevations up to about 2800 feet. This is the prime elevation of the Tincan trees; so, keep that in mind during the next storm. Don’t get complacent with areas like this that you assume are always safe.

Persistent issues:

The facets that formed on the ground in October continue to show signs of improved stability. This layer, however, is still a concern for future avalanches, especially during and after the next big storm.

WEATHER FORECAST

WESTERN PRINCE WILLIAM SOUND-

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

620 AM AKST THU JAN 8 2009

.TODAY…MOSTLY CLOUDY. ISOLATED SNOW SHOWERS IN THE LATE AFTERNOON.

HIGHS 5 BELOW TO 10 ABOVE. VARIABLE WIND 10 MPH. NORTH WIND TO 25 MPH

IN SEWARD.

.TONIGHT…CLOUDY WITH SNOW LIKELY. AREAS OF BLOWING SNOW.

ACCUMULATION OF 2 TO 5 INCHES. LOWS ZERO TO 15 ABOVE. NORTH WIND 10

TO 20 MPH WITH GUSTS TO 30 MPH.

.FRIDAY…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS 5 TO 15

ABOVE. VARIABLE WIND 10 MPH.

.FRIDAY NIGHT AND SATURDAY…PARTLY CLOUDY. LOWS 5 TO 15 BELOW

EXCEPT 10 TO 20 BELOW INLAND. HIGHS ZERO TO 10 ABOVE. VARIABLE

WIND 10 MPH.

.SATURDAY NIGHT…PARTLY CLOUDY. LOWS ZERO TO 10 BELOW.

.SUNDAY…CLOUDY WITH A CHANCE OF SNOW. HIGHS 5 TO 15 ABOVE.

.SUNDAY NIGHT AND MONDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW.

LOWS 5 TO 15 ABOVE. HIGHS IN THE UPPER TEENS TO MID 20S.

TEMPERATURE / PRECIPITATION

SEWARD 15 10 16 / 20 70 40

GIRDWOOD 0 -3 8 / 10 60 40

Thanks for checking the CNFAIC avalanche advisory. Have a great day.