Good Morning backcountry travelers, this is Matt Murphy with the Chugach National Forest Avalanche Information Center on Thursday, January 15, 2009 at 7am. This will serve as a general backcountry avalanche advisory issued 5 days a week Wednesday-Sunday for the Turnagain Arm (Turnagain Pass is the core advisory area). Local variations always occur.
Schools are closed again today due to icy roads in Anchorage. Please be careful driving.
MOUNTAIN WEATHER ROUND UP
In the last 24 hours…
-The Center Ridge weather station at 1800 feet in Turnagain Pass-
No data. We will be helping NRCS to finish repairs. The good news is that all the data for the past month has been logged it just hasn’t transmitted; so, once it is back online, we will be able to update our snowfall and temperature records.
-The AK Railroad Tunnel weather station at 490 feet near Spencer Glacier-
Reported 2.46 inches of water. Current temp is 33 (3 degrees colder than yesterday)
-Sunburst weather station at 3800 feet in Turnagain Pass-
Recorded extreme winds averaging 21-80 mph from the E with gusts to 110mph. Current temperature is 23 degrees F (3 degrees colder then yesterday)
-The Grandview weather station at 1100 feet along the railroad tracks-
seems to be having some trouble so I used the AK railroad tunnel weather station
-Surface Analysis Maps-
From 3 am Wednesday to 9pm last night…
That same strong storm from yesterday is still centered south of the Aluetians. It barely moved as it gained some strength before getting slightly weaker last night (962-967mb). The outer arm of this storm is still directly over us pulling up moisture from the south.
I was unable to get the info I usually check, but yesterday’s forecast was calling for the main flow to continue from south to north for the next couple days.
As of 5:30 am this morning…Still shows a lot of moisture moving quickly up from the south directly toward us.
Both the Middleton and Kenai radars show much less precip than yesterday over Prince William Sound and the Kenai Mountains.
-General Weather Observations-
Temps cooled down at most weather stations by 1-3 degrees. Winds have been extremely strong along ridge tops averaging as high as 80 mph with several gusts over 100 mph. The Portage Visitors Center weather station reported 6.69 inches of water in the past 24 hours. CNFAIC Staff weather stations from Seward to Girdwood recorded 2-3 inches of water in 24 hours.
PRIMARY AVALANCHE CONCERNS
-Wind slabs on top of December facets
-New storm snow on top of December facets
SECONDARY AVALANCHE CONCERNS
-Glide Cracks (see photos)
WATCH OUT SITUATIONS
-Terrain steeper than 25 degrees. Terrain under or near any avalache paths.
AVALANCHE AND SNOWPACK DISCUSSION
Avalanche conditions will remain very dangerous today. Traveling in avalanche terrain is not recommended. This includes lower angle slopes and flat terrain under avalanche paths.
We drove up to Turnagain Pass to get some visual observations from our truck yesterday. Wet snow was accumulating slightly at the higway elevation just at the crest of the Pass. Temps were cold enough on Sunburst yesterday for all that precip to fall as snow up high in the starting zones. Due to lack of visibility, we were unable to see any avalanches at Turnagain Pass, but we saw several medium to large natural avalanches between Girdwood and Portage.
Just because the weather calmed down a bit this morning, does not mean it is safe. We just had the biggest storm of the season dump tons of weight on top of a widespread weak layer of facets and buried surface hoar. Those facets were failing on themselves as sluffs over the past week even before any new weight was added. Then they became very fragile with just 5 inches of new snow of top of them on Monday and Tuesday. Now there will be very deep large slabs on top of these facets that have the potential to connect across multiple starting zones and rip out entire mountain faces or bowls. This is a recipe for very large and fatal avlanches.
Stay away from the backcountry. The mountains are showing signs that they do not want you around, and you have to play by their rules if you want to live a long life. As the saying goes, there are old pilots and bold pilots, but no old bold pilots. Personally, I would not even ski the Tincan trees today, but that is just my opinion. If you want the facts, however, most avalanche accidents occur during or within 24 hours of a storm. We are still in that window. Do not put yourself in a bad statistical situation.
WESTERN PRINCE WILLIAM SOUND-
500 AM AKST THU JAN 15 2009
…HIGH WIND WARNING IS CANCELED…
…URBAN AND SMALL STREAM FLOOD ADVISORY FOR RAIN AND MELTING SNOW
IN EFFECT UNTIL 5 PM AKST FRIDAY…
…STRONG WIND THIS AFTERNOON THROUGH LATE FRIDAY EVENING…
.TODAY…RAIN AND SNOW SHOWERS. NO SNOW ACCUMULATION. HIGHS IN
THE MID 30S TO LOWER 40S. SOUTHEAST WIND 15 TO 20 MPH. THROUGH
PORTAGE VALLEY AND TURNAGAIN ARM…SOUTHEAST WIND 25 TO 40 MPH
BECOMING EAST AND INCREASING TO 40 TO 55 MPH LATE IN THE AFTERNOON.
.TONIGHT…RAIN AND SNOW. NO SNOW ACCUMULATION. LOWS IN THE 30S.
SOUTHEAST WIND 15 TO 25 MPH. THROUGH PORTAGE VALLEY AND TURNAGAIN
ARM…EAST WIND 40 TO 55 MPH.
.FRIDAY…RAIN AND SNOW…HEAVY AT TIMES. NO SNOW ACCUMULATION. HIGHS
IN THE MID 30S TO LOWER 40S. SOUTHEAST WIND 25 TO 35 MPH EXCEPT
SOUTHEAST 55 TO 70 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.
TEMPERATURE / PRECIPITATION
SEWARD 37 34 38 / 100 100 80
GIRDWOOD 38 35 38 / 80 80 80
Thanks for checking the CNFAIC avalanche advisory. Have a great day.