Good morning backcountry travelers this is Lisa Portune with the Chugach National Forest Avalanche Information Center on Sunday, November 21st 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).
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.
The dry spell continues…no new snow has fallen in the last 8 days in Turnagain Pass. Ridgetop winds were light yesterday, averaging 5-10mph out of the northwest, while a steep inversion kept mountain temperatures on the warm side for the fourth day in a row. Temps around 4000 feet elevation hit the low 40’s yesterday while sea level temps remained in the upper teens. Skies are clear this morning above the fog while ridgetop winds are light. Temperatures this morning are close to 40F above 3000 feet while sealevel temps are 20 degrees colder. Expect sunny skies above the fog for most of the day and light northwest winds averaging 5-10mph. Warm air aloft will continue to keep temperatures inverted today. High clouds should move in later this afternoon as a low pressure system makes its way east. Unfortunately, we might see freezing rain at the lower elevations and rain at the higher elevations tonight and tomorrow until the inversion breaks. Things could get ugly.
Today the avalanche danger remains at LOW overall with pockets of MODERATE hazard underneath glide cracks. No human triggered avalanches have been reported since last Saturday. Glide cracks continue to avalanche unpredictably and remain our primary concern today. Be aware of your travel routes and avoid spending time below the cracks.
Not much has changed the past few days in overall snow stability. We are, however, seeing some of our warmest temps this morning at the 3000 ft. level where most of the glide cracks live. The photo above shows a band of glide avalanches around 2700 feet on Goat Mountain in the upper Girdwood Valley. Keep an eye out for increased glide avalanche activity today due to the warm temps. There is still plenty of good quality snow out there but also areas that are highly variable. Thinking into the future…the next weak link in our snowpack is the current snow surface, a matrix of surface hoar and crusts at the lower elevations, thin melt freeze crusts on steep southern aspects, wind crusts and windslabs above treeline, and a possible rain crust after tomorrow. We’ll see how the next snowfall bonds to these various layers.
An interesting side note…Jon was with an APU class yesterday when they saw an 800 lb. brown bear barreling down the north side of Magnum and up Sunburst. Did the warm temps up high drive the bear out of its den? Did the bear even den up yet? Sheesh!
I 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:
WESTERN PRINCE WILLIAM SOUND-
500 AM AKST SUN NOV 21 2010
…STRONG WIND THROUGH SUNDAY EVENING NEAR WHITTIER…
.TODAY…MOSTLY SUNNY IN THE MORNING THEN BECOMING PARTLY CLOUDY.
HIGHS IN THE UPPER 20S TO MID 40S…COOLEST INLAND. LIGHT WINDS
INLAND. NEAR SEWARD…NORTH WIND 25 TO 40 MPH DIMINISHING TO 15 TO 25
MPH IN THE AFTERNOON. NEAR WHITTIER…SOUTHWEST WIND 25 TO 40 MPH
WITH GUSTS TO 55 MPH.
.TONIGHT…RAIN LIKELY AFTER MIDNIGHT. A SLIGHT CHANCE OF FREEZING
RAIN INLAND AFTER MIDNIGHT. TEMPERATURES STEADY IN THE UPPER 20S TO
MID 30S. LIGHT WINDS INLAND. NEAR SEWARD…NORTH WIND 10 TO 20 MPH.
NEAR WHITTIER…SOUTHWEST WIND 15 TO 30 MPH BECOMING VARIABLE 10 MPH
IN THE EVENING. GUSTS TO 45 MPH IN TH EVENING.
.MONDAY…RAIN LIKELY. A SLIGHT CHANCE OF FREEZING RAIN INLAND IN THE
MORNING. HIGHS IN THE MID 30S TO LOWER 40S. LIGHT WINDS. THROUGH
PORTAGE VALLEY AND TURNAGAIN ARM…SOUTHEAST WIND 10 TO 20 MPH
INCREASING TO 25 TO 40 MPH IN THE AFTERNOON.
TEMPERATURE / PRECIPITATION
SEWARD 43 31 42 / 0 50 50
GIRDWOOD 29 28 38 / 0 70 70
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
recorded light northwesterly winds yesterday averaging 5-10mph. The high temp yesterday was 40F at 6pm. The current temp is 38F with winds averaging 5mph out of the northwest.
-2600′ Seattle Ridge Wx Station-
recorded light and variable winds yesterday. The current temp is 36F with winds averaging 3mph out of the northeast.
-1800′ Center Ridge Wx Station-
recorded no new snow in the last 8 days. The high temp yesterday was 27F at noon. The site stopped working at 6pm last night so no current readings. 113” of snow fell from Nov. 1-12.