Good morning backcountry travelers. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, March 27th 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).
The Friends of the Chugach National Forest Avalanche Information Center will be hosting a beacon park Today, Sunday, at Glen Alps (Flattop trailhead). Show up to hone your transceiver skills in this free event from 12-4pm. Beacon park donated by Backcountry Access.
The avalanche danger today is LOW with pockets of MODERATE for soft slab avalanches in Thursday’s storm snow. These are in scattered locations mainly in the mid to high elevations and various aspects. Also, watch for wet loose sluffing on southerly slopes. Any shallow snow cover area with over a foot of new snow also has an isolated chance for an avalanche to fail in the deeper weak snow causing a larger slide.
Today the primary concern is for soft slab avalanches in the new storm snow. Not all of the new snow has completely bonded to the old snow surfaces. This was evident in Seattle Creek yesterday where over a day old piece of hangfire (snow adjacent to an existing fracture line that remains after avalanche release) from a natural avalanche was still very ‘touchy’. A large portion was remotely triggered from around 30 feet away on the ridgeline with surface hoar involved. Also there was a report of a snowmachine triggered slide in upper Johnson Pass yesterday.
The variable underlying surfaces are hard to identify where the new snow is bonding and where it is not. Most prone are areas with over a foot of snow and at mid to upper elevations. Watch for any collapsing and cracking in the new snow, this is bulls eye data the slope could slide. These spots are scattered and can be next to tracks so it is a good reminder to always use safe travel practices, including exposing only one person at time.
Thanks to the clouds parting yesterday we had a good look around. There was some natural slab activity, likely at the tail end of the storm early Friday morning. The report from Johnson Pass also noted 2′ of new snow over icy surfaces that produced several naturals.
The mostly manageable loose snow sluffing on north aspects as well as wet loose sluffing on southern slopes that was prevalent yesterday should diminish today. Most southerly aspects will have a sun crust this morning, yet will likely soften through the day. Keep wet snow sluffing in mind on southerly slopes.
Any shallow snow cover (less than 5′) receiving over a foot of new snow has a chance for triggering a deeper avalanche breaking into the weak snow near the ground. This new load on a weak snowpack increases the danger and what to watch for is loose rotten snow under the new snow or an older slab. These spots are isolated but could be hanging the balance with no warning signs.
Outside forecast area
For people headed North to Hatcher pass, the level of concern should be heightened. It’s been a week since the fatality on Hatch peak. Despite what some media reports said about that avalanche, it was not an isolated event. Hatcher pass has an exceptionally weak snowpack with areas of hard slab and new snow on top. All backcountry use in the Talkeetna mountains should be done with an elevated sense of caution, using good judgment with terrain choices and safe travel techniques.
TIP OF FOR THE WEEKEND
Check out this video to show what happens when a skier above triggers an avalanche onto a skier below. This is a great reminder why we should only expose one person at a time. Watch your buddies from a safe spot and clear out to a safe area below before the next person rides the slope. It’s an easy ritual to follow that effectively saves lives.
Encyclopedia of avalanche terms.
The sun broke through the clouds yesterday and the winds stayed light helping to raise temperatures to over 30F and close to 40 at lower elevations – springlike. Overnight, skies have been mostly clear with temperatures dipping to around 20F with light winds. Today it looks like mostly sunny to partly cloudy skies in the afternoon with temperatures around 30F again with light southerly winds. The precipitation has moved off to the east for now but may drop a flurry or two into our region later today.
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 AKDT SUN MAR 27 2011
.TODAY…SNOW AND RAIN SHOWERS LIKELY. SNOW ACCUMULATIONS UP TO 1
INCH. HIGHS IN THE 30S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR
SEWARD. NEAR WHITTIER…SOUTHWEST WINDS 15 MPH WITH GUSTS TO 30 MPH
THIS MORNING. NEAR SEWARD…NORTH WIND 15 MPH BECOMING VARIABLE 10
MPH BY NOON. VARIABLE WINDS 10 MPH ELSEWHERE.
.TONIGHT…MOSTLY CLOUDY WITH A CHANCE OF SNOW SHOWERS. LOWS IN
THE 20S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.
.MONDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW. HIGHS IN THE MID
30S TO LOWER 40S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.
.MONDAY NIGHT…A CHANCE OF SNOW IN THE EVENING…THEN SNOW
LIKELY AFTER MIDNIGHT. LOWS IN THE MID TEENS TO LOWER 30S. LIGHT
WINDS EXCEPT EAST 10 TO 20 MPH THROUGH PORTAGE VALLEY AND
.TUESDAY…SNOW LIKELY. HIGHS IN THE 30S. LIGHT WINDS BECOMING
EAST 10 TO 15 MPH IN THE AFTERNOON. NEAR SEWARD…NORTH WIND
15 TO 20 MPH.
.TUESDAY NIGHT…SNOW LIKELY. LOWS 25 TO 35.
.WEDNESDAY THROUGH THURSDAY…RAIN AND SNOW LIKELY. HIGHS 35 TO
45. LOWS 25 TO 35.
TEMPERATURE / PRECIPITATION
SEWARD 40 26 39 / 40 30 40
GIRDWOOD 37 23 36 / 70 40 40
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
19 degrees. Variable light wind.
-2600′ Seattle Ridge Wx Station-
22 degrees. Variable light wind.
-1800′ Center Ridge Wx Station-
22 degrees. No new snow.