Good morning backcountry travelers. This is Jon Gellings with the Chugach National Forest Avalanche Information Center on Tuesday, April 5th 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 avalanche danger today has dropped a bit, to MODERATE, with pockets of CONSIDERABLE. Fresh wind slabs on steep leeward terrain are still likely to slide, so identify slopes that fit this to avoid the hazard. Any previously dry snow that gets rained could possibly fail naturally today.
We were still unable to see around into the upper start zones yesterday, furthering our suspicions of what has actually failed within the past several days. Much of what has slid could be covered up by the time we actually see the areas next.
Our biggest concern today is still the weak layers that got buried at the end of March. Northerly aspects lacking crusts in the upper portion of the snow have a higher concern than CNFAIC Staff aspects. Listening for whumpfing sounds, as well as searching for recent deeper avalanches can help clue you into this instability. Steeper slopes are the most likely places to find this, so assessing the snow before you travel on it is recommended.
Wind slabs that developed with the strong winds may still be sensitive, but are likely to be less reactive than earlier in the storm. If they do show themselves, they will likely show shooting cracks, followed by cascading snow downhill.
Any amount of open sun on this new snow will likely start the sun-affect types of instabilities, so be aware of this if recreating on South facing slopes in the afternoon. Looking for recent avalanches is the best type of bulls eye clue to showing what has been unstable recently, and what kind of slope is still hanging in the balance. Aspects and angles showing this recent activity are the ones to be avoided today.
Encyclopedia of avalanche terms.
Winds are still going to be able to transport some amount of snow, so they could contribute to instabilities today. Temperatures look like they will be similar to yesterday, but then dropping significantly tonight. There is a small amount of precipitation out there today, so we could see some amount hit our area, but not enough will fall to increase the danger a large amount.
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 TUE APR 5 2011
.TODAY…SNOW AND RAIN. SNOW ACCUMULATION UP TO 2 INCHES OVER HIGHER
ELEVATIONS. HIGHS IN THE MID 30S TO MID 40S. WEST WIND 15 MPH.
.TONIGHT…PARTLY CLOUDY. ISOLATED RAIN AND SNOW SHOWERS IN THE
EVENING. LOWS IN THE LOWER 20S TO LOWER 30S. VARIABLE WIND TO 10 MPH.
NEAR SEWARD…NORTH WIND 10 TO 25 MPH.
.WEDNESDAY…MOSTLY SUNNY IN THE MORNING THEN BECOMING PARTLY
CLOUDY. HIGHS IN THE MID 30S TO MID 40S. NORTHWEST WIND 10 TO
15 MPH EXCEPT NORTH 15 TO 30 MPH NEAR SEWARD.
.WEDNESDAY NIGHT…CLOUDY. SNOW LIKELY AFTER MIDNIGHT. LOWS IN THE
MID 20S TO LOWER 30S. VARIABLE WIND 10 MPH. THROUGH PORTAGE VALLEY
AND TURNAGAIN ARM…VARIABLE WIND 10 MPH BECOMING EAST 10 TO 25 MPH
TEMPERATURE / PRECIPITATION
SEWARD 46 29 42 / 80 20 0
GIRDWOOD 39 25 37 / 80 20 0
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
22 degrees. ENE wind 16mph gusting to 28mph.
-2600′ Seattle Ridge Wx Station-
26 degrees. SE wind 21mph gusting to 29mph.
-1800′ Center Ridge Wx Station-
30 degrees. 1 inch new snow.