Good morning backcountry travelers this is Matt Murphy with the Chugach National Forest Avalanche Information Center on Friday, November 19th 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 on Chugach National Forest lands 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.
-TEMPS: Have continued to increase slightly at elevations above 2400′ but decrease slightly at sea-level. There is still a temperature inversion this morning; so, temps are colder at sea level than up high on the ridges where temps are above freezing (see weather station summary at the bottom of this page) These warm temps may affect the glide cracks.
-PRECIP: There has been zero (0.0 inches) precip that has fallen in 24 hours, and NOAA is forecasting zero(0.0 inches) of precip for today
-WIND: Has been light with moderate gusts in the past 24 hours in the mountains around Turnagain Pass. Once again, NOAA is forecasting strong wind near Whittier this afternoon. Yesterday, the wind was transporting snow on the ridges toward Whittier on peaks like Carpathian. Mile 43 Peak recorded the strongest winds in the region yesterday, but all CNFAIC Staffs recorded light to moderate winds.
The avalanche danger rating will remain at LOW with pockets of MODERATE. There are wind slabs near ridges and prominent terrain features. Plus, there are glide cracks widespread throughout the region.
The wind slabs have been reactive to human-triggers since last Saturday 11/13/2010 when a small to medium sized avalanche was triggered near Superbowl (see photo gallery). These wind slabs have become less reactive to human-triggers, but there are still some pockets of concern on steep unsupported terrain. An example of unsupported terrain are pockets of snow above cliff bands and steep basketball-shaped rollovers. Even though the weather stations recorded light to moderate winds yesterday, we observed wind transporting snow on most ridges in the forecast area.
The glide cracks and glide avalanches continue to be present, with new ones being observed region-wide on a daily basis. Be aware of your travel routes and try to avoid spending time below the cracks. Research has shown it is nearly impossible to predict when these cracks will release. The only way to reduce your risk from glide avalanches is to avoid traveling below the obvious cracks.
This photo shows the South face of Cornbiscuit taken on 11-16-10. For scale take note that the crack is 4-6 feet deep. The glide crack on the left hand side of this photo has already avalanched; while, the glide crack on the right is still a hazard that could avalanche any day. Avoid traveling underneath glide cracks just like the one on the right hand side of this photo.
We continue to see surface hoar at lower elevations, but it has not been observed at mid or upper elevations. A report of a thin melt/freezed crust on the surface of sunny slopes was reported yesterday.
The NWS weather forecast for:
WESTERN PRINCE WILLIAM SOUND-
500 AM AKST FRI NOV 19 2010
…STRONG WIND THROUGH THIS AFTERNOON NEAR WHITTIER…
.TODAY…SUNNY. HIGHS IN THE MID TEENS TO LOWER 30S EXCEPT IN THE
UPPER 30S NEAR SEWARD AND WHITTIER. LIGHT WINDS EXCEPT NORTH
10 TO 20 MPH NEAR SEWARD.
.TONIGHT…CLEAR. LOWS IN THE SINGLE DIGITS TO LOWER 30S…COOLEST
INLAND. LIGHT WINDS INLAND. NEAR WHITTIER…SOUTHWEST WIND 20 TO 35
MPH WITH GUSTS TO 50 MPH. NEAR SEWARD…NORTH WIND 15 TO 25 MPH.
.SATURDAY…MOSTLY SUNNY. HIGHS IN THE LOWER 20S TO LOWER 40S…
COOLEST INLAND. LIGHT WINDS EXCEPT WEST 20 TO 35 MPH NEAR WHITTIER.
NEAR SEWARD…NORTH WIND 10 TO 20 MPH.
TEMPERATURE / PRECIPITATION
SEWARD 36 25 38 / 0 0 0
GIRDWOOD 23 10 25 / 0 0 0
WEATHER STATION SUMMARY for Turnagain Pass:
3800′-Sunburst Wx Station
Temp (5am): 32 (5 degrees warmer than yesterday morning)
Winds: In last 24 hours winds have been light averaging 6-10mph with a moderate max gust of 20 mph
2400′-Seattle Ridge Wx Station
Temp (5am): 33 (2 degrees warmer than yesterday morning)
Winds: In last 24 hours have been light averaging 1-13mph with a moderate max gust of 21mph.
1800′-Center Ridge Wx Station
Temp (5am): 24 (6 degrees colder than yesterday morning)
Precip: 0.0 inches of water, 46″ of total snopack depth (1 inch less due to settlement)
The next advisory will be issued tomorrow morning at 7am. If you get out in the backcountry send us your observations using the button at the top of this page or call and leave a message at 907-754-9369. Thanks and have a great day.