Good morning backcountry travelers, this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Friday, November 20th. This will serve as a general backcountry avalanche advisory issued for the Turnagain Arm area (Turnagain Pass is the core advisory area). Local variations always occur. This advisory should be used as a general early winter safety message and is less detailed than standard advisories.
Clear and cold has been the story this week. The NWS forecast office is forecasting a warm up and an increased chance of snow showers this weekend. Three low pressure systems are setting off shore in the gulf and could be the start of a weather pattern change. Look for tempts to return to normal next week. We are already seeing warmer temperatures this morning. Girdwood is 9 deg F and Center Ridge in Turnagain Pass is 14 deg F. We currently have 6-10 inches at the highway elevation of 1000ft in Turnagain Pass, 15 -17 inches at tree line, 0-30 inches in the alpine due to wind erosion or deposition. Last weekend’s high winds really moved snow around. Many alpine areas are bare and leeward aspects are very wind loaded. See our photo gallery for the first significant avalanche of the season. We heard of it on Wednesday. It’s a couple hundred feet wide and ran 500 vertical or so. It looks like the crown is approximately 2 feet deep and probable failed on the near ground facets. I can’t tell if it was human or naturally triggered. If you have more beta on this avy, let us know. There are lots of track all around it. This avalanche occurred on the sunny side (west side, AKA: Repeat Offender) of Turnagain Pass, directly above the snow stake. This area is wind loaded, and holds wind slabs most often.
Our current snowpack is still pretty thin and has a melt freeze crust in the middle of it from early November. This crust extends up to approximately 2000 ft. We also have lots of wind slabs on multiple aspects due to shifting wind directions. Winds ripped on the 14th, with gust in the 60’s out of the NW. To add to our early season snowpack the last weeks cold temperatures have faceted the whole thing. A significant temperature gradient drove the faceting process most of the week. I found near surface facets, near crust facets, and faceted crystals at the ground. Faceted snow crystals can be described as sugar snow and does not bond well with it’s neighbor crystals.
Take your time getting back into winter. It would suck to get pushed through the rocks early season. Make time to go through your gear and practice your rescue skills. No time like the present to discuss companion rescue with your backcountry traveling partners. Your life is in their hands. Check out our training calendar for avalanche classes.
We will start our 7 day a week advisory schedule when additional snow falls or changes warrant.
The NWS forecast for:
WESTERN PRINCE WILLIAM SOUND-
500 AM AKST FRI NOV 20 2009
.TODAY…MOSTLY CLOUDY. SCATTERED SNOW SHOWERS INLAND AND
NUMEROUS SNOW SHOWERS ALONG THE COAST. SNOW ACCUMULATION UP
TO 2 INCHES…MAINLY ALONG THE COAST. HIGHS IN THE MID TEENS
TO LOWER 20S INLAND AND MID 20S TO LOWER 30S ALONG THE COAST.
VARIABLE WIND TO 15 MPH.
.TONIGHT…SNOW LIKELY. SNOW ACCUMULATION 1 TO 3 INCHES. LOWS
5 TO 15 ABOVE INLAND AND 15 TO 25 ALONG THE COAST. LIGHT WINDS.
.SATURDAY…SNOW LIKELY. SNOW ACCUMULATION 1 TO 3 INCHES. HIGHS
IN THE LOWER 20S TO LOWER 30S…WARMEST ALONG THE COAST. LIGHT
.SATURDAY NIGHT…MOSTLY CLOUDY WITH A CHANCE OF SNOW. LOWS IN
THE 20S. VARIABLE WIND TO 10 MPH.
.SUNDAY…CLOUDY WITH A CHANCE OF SNOW AND RAIN. HIGHS IN THE
LOWER TO MID 30S. EAST WIND 10 TO 20 MPH.
.SUNDAY NIGHT…SNOW AND RAIN LIKELY. LOWS 25 TO 35.
.MONDAY…CLOUDY WITH A CHANCE OF SNOW AND RAIN. HIGHS IN THE 30S.
.MONDAY NIGHT AND TUESDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW
AND RAIN. LOWS IN THE 20S. HIGHS IN THE 30S.
.TUESDAY NIGHT…MOSTLY CLOUDY WITH A CHANCE OF SNOW. LOWS 15 TO 25.
.WEDNESDAY THROUGH THANKSGIVING DAY…MOSTLY CLOUDY WITH A CHANCE
OF SNOW. HIGHS IN THE 20S. LOWS 15 TO 25.
TEMPERATURE / PRECIPITATION
SEWARD 25 22 32 / 60 60 60
GIRDWOOD 17 17 31 / 40 60 60