Good morning backcountry travelers. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Sunday, April 3nd 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).
Hone your beacon skills and meet some new folks – The Friends of the CNFAIC and the Avy Savvy Gals will be operating the BCA beacon park at the Glen Alps trailhead parking in Anchorage today from 1-4pm. This is an excellent thing to do on a stormy, dangerous day in the backcountry, like today.
The avalanche danger is CONSIDERABLE on all slopes over 30 degrees with pockets of HIGH danger on steeper slopes at higher elevations. Strong winds and new snow have overloaded recently buried weak layers as well as created sensitive wind slabs. Widespread storm snow sluffing as well as wet activity at lower elevations with rain on snow is likely.
If it’s snowing and it’s blowing expect the snow to move. Recent and ongoing strong winds and close to a foot of new snow overnight with 6 – 10” expected today (likely more at the higher elevations) has elevated the avalanche danger. Stay clear of avalanche run out zones such as gully bottoms and out from under all steep slopes.
We have two main problems out there:
Persistent slab avalanches –
These are deep and dangerous avalanches that can be found where 2 to 4 feet of snow from the past week overlies the old wind hammered March surface. Surface hoar and/or facets are sandwiched between these two layers and continue to be very reactive. Several avalanches have recently slid on these layers but many more hang in the balance. These slabs can release naturally with the added weight of the new snow or be initiated by a new wind slab breaking off from above. They are most common in the mid to upper elevations, including all aspects, and could propagate wide and run into the drainage bottoms.
Wind slabs and storm snow –
Winds have been gusting into the 60’s and higher for the past 24 hours and are transporting snow onto leeward slopes. These fresh wind slabs and cornices will be widespread and very ‘touchy’, likely to fail on their own today. Many southerly and mid elevation slopes have a variable crust under the last 24 hours of new snow which will encourage any wind slabs or storm snow sluffing to run fast and far. At and below treeline watch for wind slabs and storm snow to be sitting on a crust as well, allowing for soft slabs and sluffing likely on the steeper rollovers.
If skies clear enough for travel, expert level snow and terrain assessment skills will be required today.
Encyclopedia of avalanche terms.
Obscured skies, afternoon snow showers and gusty wind were the scene yesterday as the approach of the storm over the gulf pushed into our area. Overnight 10 inches of snow fell at the center ridge SNOTEL site and the winds have been over 40mph with gusts over 70 from the east on the ridgelines. Temperatures have been in the 20’s at all elevations above 1000′ with the rain snow line near 1000′. Today we should see anCNFAIC Staff 6-10” of snow and continued strong winds, gusting in the 50’s. Expect limited visibility with the low clouds and temperatures to remain in the mid 20’s. Snow accumulation looks to decrease a bit overnight and into tomorrow.
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 APR 3 2011
…STRONG WIND THROUGH THIS AFTERNOON THROUGH PORTAGE VALLEY AND
.TODAY…SNOW AND RAIN. NO SNOW ACCUMULATION. HIGHS IN THE MID
30S TO UPPER 40S. NORTH TO EAST WIND 15 TO 30 MPH. THROUGH PORTAGE
VALLEY AND TURNAGAIN ARM…EAST 40 TO 55 MPH DIMINISHING TO 15 TO 30
MPH IN THE AFTERNOON.
.TONIGHT…NUMEROUS RAIN AND SNOW SHOWERS. SNOW ACCUMULATION UP TO 1
INCH. LOWS IN THE UPPER 20S TO MID 30S. NORTH TO EAST WIND 10 TO 20
.MONDAY…CLOUDY WITH SCATTERED RAIN AND SNOW SHOWERS. HIGHS IN THE
UPPER 30S TO UPPER 40S. SOUTHEAST WIND 10 TO 15 MPH.
.MONDAY NIGHT…SCATTERED RAIN AND SNOW SHOWERS IN THE
EVENING…THEN NUMEROUS RAIN AND SNOW SHOWERS AFTER
MIDNIGHT. LOWS IN THE UPPER 20S TO MID 30S. SOUTHEAST WIND 10 TO
15 MPH EXCEPT EAST 15 TO 25 MPH THROUGH PORTAGE VALLEY AND
.TUESDAY…RAIN AND SNOW LIKELY IN THE MORNING…THEN RAIN LIKELY IN
THE AFTERNOON. HIGHS IN THE UPPER 30S TO MID 40S. NORTHEAST WIND 15
MPH EXCEPT EAST 10 TO 25 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN
.TUESDAY NIGHT…MOSTLY CLOUDY WITH ISOLATED SNOW SHOWERS. LOWS
IN THE 20S.
.WEDNESDAY…MOSTLY CLOUDY. HIGHS 35 TO 45.
TEMPERATURE / PRECIPITATION
SEWARD 43 34 43 / 100 60 40
GIRDWOOD 42 32 42 / 80 60 40
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
Currently 20 degrees. East wind 30mph gusting over 50mph.
-2600′ Seattle Ridge Wx Station-
25 degrees. SE wind 25mph gusting over 45mph.
-1800′ Center Ridge Wx Station-
28 degrees at 6am. 10 inches new snow recorded.