Good morning backcountry travelers. This is Jon Gellings with the Chugach National Forest Avalanche Information Center on Wednesday, March 9th 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 continues to be LOW with pockets of MODERATE. Any triggered avalanche has the possibility of stepping down into older weak layers, creating a larger slide. Hard wind slabs which get triggered have the potential of fracturing down to these layers, and are most suspected on steep rollovers on wind loaded slopes and near rocky outcroppings and gullies. A slight chance remains than any sun-triggered sluffs happening on South aspects could also break down into the deeper weak layers.
Ridgelines yesterday had light breezes, which helped keep the snow surface cool. Further down on Southern slopes was a different story however, with pockets of soft snow turning into knee-high wet snow, especially below 2500 ft. People are able to trigger point releases in this warm surface snow, as evidenced by Wendy’s “push-a-lanche” below.
Places where natural point releases could start include near steep rocky outcroppings, convex rollovers, and places where trees stick up through the snow.
On non-sun-affected slopes, surface hoar is growing as well, ranging from 1-2cm down low to 2mm in upper elevations. Surface hoar and sun crusts on the surface could make for an interesting avalanche cycle when we get some new snow.
Our current stability concerns remain the same, where a shallow snowpack on a steep slope is where a person could possibly trigger a slab avalanche. The biggest concern we have right now would be triggering an avalanche which breaks into the older weak snow near early season crusts. Looking at these faceted snow grains is easier in scoured spots, because they are closer to the surface. This poorly structured snowpack is most predominant in areas and regions with a shallow snow depth, and is not expected to leave our area until a major jolt to the snowpack occurs. Unfortunately, since today is likely not that day, we can not write these instabilities off.
Encyclopedia of avalanche terms.
Winds are not expected to become strong enough to blow snow around. Temperatures are forecasted to get back into the 30s. There is no new precipitation being forecasted for today.
Kevin 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 AKST WED MAR 9 2011
.TODAY…SUNNY. HIGHS IN THE 30S. LIGHT WINDS EXCEPT NORTH 10 TO
15 MPH NEAR SEWARD.
.TONIGHT…CLEAR. LOWS 15 TO 25 ABOVE…COOLEST INLAND. LIGHT
WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.
.THURSDAY…SUNNY. HIGHS IN THE LOWER TO MID 30S. LIGHT WINDS
EXCEPT NORTH 10 MPH NEAR SEWARD.
TEMPERATURE / PRECIPITATION
SEWARD 39 20 34 / 0 0 0
GIRDWOOD 34 16 31 / 0 0 0
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
Temperature 18 degrees. NE wind 17mph gusting to 26mph.
-2600′ Seattle Ridge Wx Station-
Temperature 21 degrees. SE wind 11mph gusting to 15mph.
-1800′ Center Ridge Wx Station-
Temperature 21 degrees. No new snow.