Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Friday February 5th at 7 am. 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).
Fund Raiser tonight at Alyeska Resort’s Sitzmark for the Alyeska Avalanche Dog Program. These dogs and handlers are great assets to our community. Starts at 7pm.
I got excited when I saw snow falling last night around dinner time. That short lived smattering of precip is, however; all we received in the advisory area. It looks like our chances of snow increase today, tonight, and through the weekend. The satellite shows a low pressure system to our southeast spinning in our direction. The radar is not showing this system yet, but has scattered precipitation represented. A slight inversion is in place again this morning with sea level temps at 17 deg F and ridge temps as high as 22 at the top of Alyeska’s chair 6. Yesterday’s winds were calm to light out of the east. Winds have picked up in the last 4-6 hours with easterly gusts to 22 mph.
Today’s avalanche danger for the Turnagain Arm area will remain at LOW with pockets of MODERATE.
Limited change in our snowpack this week. As Matt has eluded to in earlier advisories, we are starting to see some spacial variability in our mountain snowpack. This is normal when weak layers hang out as long as the ice crust of concern has. One month ago we received rain to 2500 ft. This really split our snowpack into two zones. Elevations above this elevational band continue to see fair to good stability. With the occasional wind slab and ridge top instabilities you would expect. Below 2500 ft we are seeing the weak layer associated with this crust persist. Stability tests are starting to show decreased stability in some areas. Check out our youtube videos to see the energy building in our snowpack. I think that the 1.5 to 2 ft of snow that is resting on top of this crust is settling into a more cohesive slab of snow. This denser slab of snow is now able to tranfer the impact of a skier, rider, or snow stability test down to the weak layer. Remember that the weight of a skier or snowboarder is transferred ~3 ft deep into the snowpack and a machiner is ~4 ft. Our instability is ~2 ft deep.
Our avalanche hazard will increase to moderate when additional snow or rain falls on our snowpack. Below 2500 ft is where we will see avalanche activity first.
Our weather history, snowpit data, and field observations all hint toward the rain crust being more developed below 3000′. That’s why places like Widowmaker Peak, CNFAIC Staff Seattle Ridge bowls and Eddies on the non-motorized side of Turnagain Pass are areas for future concern. These places have steep slopes at these lower elevations. CNFAIC Staff places with steep slopes at lower elevations include Placer Valley, Girdwood Valley, Kern and Peterson Creeks.
Always remember that safe backcountry travel requires training and experience. You control your own risk by choosing where, when, and how you travel.
WEATHER FORECAST (National Weather Service)
WESTERN PRINCE WILLIAM SOUND-
500 AM AKST FRI FEB 5 2010
.TODAY…SNOW. SNOW ACCUMULATION UP TO 3 INCHES. HIGHS IN THE
LOWER 20S TO LOWER 30S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR
.TONIGHT…SNOW. SNOW ACCUMULATION 4 TO 8 INCHES. NEAR STEADY
TEMPERATURES IN THE LOWER 20S TO LOWER 30S. EAST WIND 10 MPH EXCEPT
NORTH 20 MPH NEAR SEWARD.
.SATURDAY…SNOW IN THE MORNING…THEN A CHANCE OF SNOW IN THE
AFTERNOON. SNOW ACCUMULATION 1 TO 3 INCHES. HIGHS IN THE UPPER
20S TO MID 30S. SOUTH AND EAST WIND 10 TO 15 MPH.
.SATURDAY NIGHT…CLOUDY WITH A CHANCE OF SNOW. LOWS IN THE 20S.
SOUTHEAST WIND 10 TO 25 MPH.
.SUNDAY…SNOW. HIGHS IN THE MID 20S TO LOWER 30S. SOUTHEAST WIND
.SUNDAY NIGHT…SNOW LIKELY. LOWS IN THE TEENS.
.MONDAY AND MONDAY NIGHT…MOSTLY CLOUDY WITH A CHANCE OF SNOW.
HIGHS IN THE 20S. LOWS IN THE TEENS.
TEMPERATURE / PRECIPITATION
SEWARD 28 27 30 / 80 100 80
GIRDWOOD 28 28 32 / 60 100 80
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
recorded light southeasterly winds yesterday. The current temp is 18F (5 degrees warmer than yesterday) with winds averaging 8-16 mph out of the east with gusts of 12-22.
-2600′ Seattle Ridge Wx Station-
recorded light southeasterly winds yesterday. Winds are currently averaging 10-16 mph out of the southeast with gust of 17-22.
-1800′ Center Ridge Wx Station-
recorded no new snow in the last 24 hours. The current temp is 11F (2 degree warmer than yesterday) with a total snowpack depth of 62 inches.
Thanks for checking today’s avalanche advisory. The next one will be posted tomorrow Saturday, February 6th.