Good morning backcountry travelers. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Saturday, April 16th 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).
*Today will be the last advisory for the 2010/2011 season.
*Throughout the remaining two weeks of April, periodic updates will be posted.
Congratulations to Emilie Fetscher! She has won the grand prize in our observations contest and will receive a new beacon of her choice. Thank you to everyone who has sent in snow and avalanche observations throughout the year. These have been exceedingly beneficial for us in our operations and forecasts.
Today the avalanche danger will rise to MODERATE for wet snow avalanches throughout the day as the sun and warm temperatures warm the snow. Human initiated wet snow sluffing will be possible on steep southerly slopes. In addition, areas with new snow from Thursday have a MODERATE danger for lingering wind slabs sitting above buried surface hoar on higher elevation northerly aspects.
Activity seen or reported yesterday included point release wet snow avalanches on steep south slopes, most of these were small to medium but a few were a bit larger and gouged down to the ground. Also, there were a couple small glide avalanches and a few manageable wind slabs on steep north slopes. Several larger avalanches were seen in upper Lynx Creek, as well as south of the Johnson Pass trail head, that are suspected to be wind slab/soft slabs in Thursday’s, April 14th, storm snow.
We continue to have both wet and dry avalanche concerns. The trend will be for these to be remain tomorrow, Sunday April 17th, as well.
Wet avalanches on east through south through west aspects will again be a concern for today. Direct sun, warm ambient air temperatures and calm winds should soften the moderate overnight refreeze as the day progresses. By noon rollerballing and point release slides will be possible to initiate.
Any wet slab and glide avalanche activity is hard to pin down due the complex nature of these types of avalanches. These can release on their own at any time so be aware you are not hanging out in a run out zone under slopes and gullies.
Though we know the snowpack is warming and we have seen some wet avalanche activity, the bona fide spring thaw, when the mountains really begin the shed their snow, has yet to hit.
Many north aspects continue to harbor soft settled powder. Poking around yesterday I was able to find surface hoar on ridgelines underneath wind slabs formed in Thursday’s snow. These were still somewhat sensitive with a kick and I suspect this will be the case again today. Areas with the most snow from Thursday will be the most prone, namely Johnson Pass and Turnagain Pass. Some good old assessing and prodding in the new snow before committing to a steep line will be a good idea to help keep from being flushed.
Finally, there still exists a chance for triggering an avalanche that breaks into the deeper layers of surface hoar. This is in the back of my mind considering the looks of the Lynx Creek slide, which may have “stepped down” to a deeper weakness.
Encyclopedia of avalanche terms.
The sun beat down yesterday for a true springtime feel. Temperatures at 4000′ warmed to above 32F and at 1000′ approached 50 degrees. Winds were light and variable adding a slight breeze to offset a very cooked feel. Overnight, skies have remained clear and temperatures have only dropped to near 30F at 1000′ and upper 20’s at 3500′. Winds are currently light and variable. Today should be a copy of yesterday with sunny skies and springtime temperatures of near 50F at 1000′ and above freezing at 3500′. Winds are forecast to be light from the north.
Tomorrow we will post an end of season/springtime avalanche condition wrap up. We are still taking observations! Give us a call at 754-2369 or send them to us using the button at the top of this page.
Thanks for tuning into our avalanche advisories this season and have a great spring and summer!
The NWS weather forecast for:
WESTERN PRINCE WILLIAM SOUND-
500 AM AKDT SAT APR 16 2011
.TODAY…SUNNY IN THE MORNING…THEN PARTLY CLOUDY IN THE AFTERNOON.
HIGHS IN THE MID 40S TO MID 50S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR
.TONIGHT…PARTLY CLOUDY IN THE EVENING…BECOMING MOSTLY CLEAR BY
MIDNIGHT. LOWS IN THE MID 20S TO LOWER 30S. LIGHT WINDS EXCEPT WEST
10 TO 20 MPH NEAR WHITTIER.
.SUNDAY…MOSTLY SUNNY. HIGHS IN THE MID 40S TO LOWER 50S.
VARIABLE WIND 10 MPH EXCEPT WEST 10 TO 20 MPH NEAR WHITTIER.
.SUNDAY NIGHT…MOSTLY CLEAR. LOWS AROUND 30. VARIABLE WIND 10 MPH.
.MONDAY…MOSTLY SUNNY. HIGHS IN THE MID 40S TO LOWER 50S.
VARIABLE WIND 10 MPH.
.MONDAY NIGHT…MOSTLY CLEAR. LOWS 25 TO 35.
.TUESDAY…MOSTLY SUNNY. HIGHS 45 TO 55.
TEMPERATURE / PRECIPITATION
SEWARD 52 31 48 / 0 0 0
GIRDWOOD 47 28 48 / 20 20 0
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
28 degrees. Light variable winds.
-2600′ Seattle Ridge Wx Station-
30 degrees. Light variable winds.
-1800′ Center Ridge Wx Station-
30 degrees. No new snow.