Turnagain Pass

Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Saturday, January 23rd 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).

ANNOUNCEMENTS

Our Summit Lake Area Advisory started yesterday. It will be a general advisory posted on Friday and Saturday morning. The Summit Lake Area is part of the Chugach National Forest, it has been a goal of the CNFAIC to include more of the Forest for 9 years. Check it out !

WEATHER ROUNDUP

Hindcast (Last 24 hours)

3800′ -Sunburst Wx Station-

Current temp is 24 (same as yesterday) Winds have been light averaging 8mph out of the east with a gusts of 9-11 mph. The winds are increasing slightly this morning.

2400′-Seattle Ridge Wx Station-

Winds have been calm to light averaging 1-4 mph out of the W with gusts of 3-6. We are currently replacing the temperature sensor on this station.

1800′-Center Ridge Wx Station-

Current temp is 18 (1 degrees warmer than yesterday) Zero inches of water and zero inches of new snow has fallen. Total snowpack is 66″.

Even larger temperature inversions in place today. Girdwood has a 16 deg difference from valley to ridge and Summit lake has a huge 26 degrees difference. Summit lake is the cold spot with 0 degrees F. It looks like anCNFAIC Staff nice day in store with clear skies on the radar and light cloud cover on the satellite. We’re under a 991 mb low trough in southcentral that is hemmed in by two high pressure ridges to the east and west. This setup will make stronger winds likely near Whittier and Seward today. Winds have picked up on Alyeska and Max’s this morning, with gusts to 22 mph.

Forecast

AKZ125-240100-

WESTERN PRINCE WILLIAM SOUND-

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKST SAT JAN 23 2010

…STRONG WIND TODAY NEAR WHITTIER…

.TODAY…SUNNY. HIGHS IN THE 20S. LIGHT WINDS EXCEPT NORTH 20 TO

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

.TONIGHT…PARTLY CLOUDY. PATCHY FOG AFTER MIDNIGHT. LOWS IN THE

LOWER TEENS TO LOWER 30S…COLDEST INLAND. LIGHT WINDS EXCEPT

NORTH 15 TO 25 MPH NEAR SEWARD.

.SUNDAY…MOSTLY SUNNY IN THE MORNING THEN BECOMING MOSTLY

CLOUDY. PATCHY MORNING FOG. HIGHS IN THE LOWER 20S TO LOWER 30S.

VARIABLE WIND 10 MPH EXCEPT NORTH AND WEST 15 TO 25 MPH NEAR SEWARD

AND WHITTIER.

.SUNDAY NIGHT…MOSTLY CLOUDY WITH ISOLATED SNOW SHOWERS. LOWS

15 TO 25…COLDEST INLAND. LIGHT WINDS EXCEPT NORTH AND WEST 15 TO 30

MPH NEAR SEWARD AND WHITTIER.

.MONDAY…MOSTLY CLOUDY IN THE MORNING THEN BECOMING PARTLY

CLOUDY. HIGHS IN THE LOWER 20S TO LOWER 30S. LIGHT WINDS EXCEPT NORTH

AND WEST 15 TO 30 MPH NEAR SEWARD AND WHITTIER.

TEMPERATURE / PRECIPITATION

SEWARD 28 19 30 / 0 0 0

GIRDWOOD 21 15 19 / 0 0 0

AVALANCHE DISCUSSION

Todays avalanche hazard will remain at MODERATE.

The main avalanche concern continues to be the rain crust underneath the 1.5-2.5 feet of newer snow especially between 2000′-3000′. This slippery rain crust formed on Thursday Jan 7 and is widespread on all aspects from Girdwood to Seward.

Yesterday we had the weather pleasure of working on Seattle Ridge. Checking out the snow stability in Warmup and Zero Bowls proved that there is lots of variability in our current snowpack. Without even getting back on our sleds we found very different conditions between a west aspect and a northeast aspect. No surface hoar or buried rain crust on south and west aspects but a thin sun crust was evident. The northeast aspect was much thinner and had the buried rain crust present along with surface hoar on the surface. Both these pits were dug at 3070 ft and only 200 yards apart.

Our test scores were once again indicating moderate stability. CTM13Q2, CTH20Q2 (x2). CNFAIC Staff clues to our moderate stability include: a boot pack straight up Goat Couloir, no new avalanche activity reported, and numerous steep lines in Turnagain Pass. All these examples show pretty good stability at the present time.

However, we definitely have the three main ingredients for an avalanche: a slab (the new 1.5-2.5 feet of snow) on top of a weaker layer (last week’s 6 inches of light dry snow) on top of a slippery bed surface (rain crust). Parts of our current snowpack and this advisory point toward low avalanche danger. However, I think of it like this. The danger scale only has one more level below our current rating of moderate. I know that stability could be better, thus I’m reserving the low for such a snowpack.

Terrain management is key right now. If big lines are on your agenda-keep big eyes wide open. Make good risk assessments, travel one at a time, watch your partner, have an escape route, use terrain that avoids terrain traps, and have a rescue plan with all the rescue equipment needed for companion rescue. In the backcountry you are the rescue party. When responding to avalanche burials, organized rescue is organized recovery.

Always remember that safe backcountry travel requires training and experience. You control your own risk by choosing where, when, and how you travel.

Thanks for checking today’s avalanche advisory. The next one will be posted tomorrow Sunday, January 24th.