Good morning backcountry travelers this is Matt Murphy with the Chugach National Forest Avalanche Information Center on Thursday, November 18th 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 increased by up to 20 degrees in 24 hours in the mountains around Turnagain Pass. There is a temperature inversion this morning; so, temps are colder at sea level than up high on the ridges (see weather station summary at the bottom of this page) This change in temperature 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. NOAA is forecasting strong wind near Whittier today. Wind can change the avalanche hazard quickly.
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 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 areas of concern on steep unsupported terrain. An example of unsupported terrain are pockets of snow above cliff bands and steep basketball-shaped rollovers.
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 has already avalanched on the left hand side of this photo, while the glide crack on the right is still a hazard and 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.
The NWS weather forecast for:
WESTERN PRINCE WILLIAM SOUND-
500 AM AKST THU NOV 18 2010
…STRONG WIND THROUGH THIS AFTERNOON NEAR WHITTIER…
.TODAY…MOSTLY SUNNY. HIGHS IN THE UPPER 20S TO MID 30S.
LIGHT WINDS EXCEPT NORTH WIND 15 TO 30 MPH NEAR SEWARD. NEAR
WHITTIER…SOUTHWEST WIND 20 TO 35 MPH WITH GUSTS TO 55 MPH.
.TONIGHT…MOSTLY CLEAR. LOWS 10 TO 25 ABOVE…COOLEST INLAND.
LIGHT WINDS INLAND. NEAR SEWARD…NORTH 15 TO 25 MPH. NEAR
WHITTIER…SOUTHWEST WIND 25 TO 35 MPH.
.FRIDAY…SUNNY. HIGHS IN THE MID 20S TO UPPER 30S. LIGHT WINDS
INLAND. NEAR SEWARD AND WHITTIER…NORTH TO WEST WIND 15 TO 25 MPH.
TEMPERATURE / PRECIPITATION
SEWARD 36 21 37 / 0 0 0
GIRDWOOD 30 11 33 / 0 0 0
WEATHER STATION SUMMARY for Turnagain Pass:
3800′-Sunburst Wx Station
Temp (4am): 25 (9 degrees warmer than yesterday morning)
Winds: In last 24 hours winds have been light averaging 5-10mph with a moderate max gust of 20
2400′-Seattle Ridge Wx Station
Temp (5am): 31 (14 degrees warmer than yesterday morning)
Winds: In last 24 hours have been light averaging 2-14mph with a moderate max gust of 25mph.
1800′-Center Ridge Wx Station
Temp (5am): 30 (20 degrees warmer than yesterday morning)
Precip: 0.0 inches of water, 47″ of total snopack detph (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.