Good morning backcountry travelers this is Kevin Wright with the Chugach National Forest Avalanche Information Center on Friday, March 25th 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 this Sunday at Glen Alps. Show up to hone your transceiver skills in this free event. Stay tuned for more information. Beacon park donated by Backcountry Access.
Today’s avalanche danger rating is MODERATE for new storm snow and fresh wind slab. The 6-9 inches that fell yesterday are significant because of the old crusty surface conditions. Human triggered avalanches will be possible today. Be on the lookout for deeper storm snow and wind slab near the ridges at higher elevations.
The storm yesterday had some intensity in the afternoon and dropped more snow than was predicted. Upper elevations in Girdwood got 7-9 inches. Turnagain Pass got 6-8 inches above 2000 feet. Any new snow right now is a heads up event that deserves some serious scrutiny.
The primary concern is the relationship between the storm snow and the old surface. Field observations yesterday confirmed that the new snow was not bonding well to the stiff, crusty, old surface layers. This bonding also gets worse as you increase in elevation. Lower down, where the temperature is warmer and the snow is wetter, the snow should stick reasonable well. Higher up near the ridges expect colder, drier snow and easy shears of the new snow. This could become dangerous if the new snow is stiff enough to form slabs and deep enough to cause damage. Today is a day that requires constant evaluation to figure out our new conditions.
I don’t expect avalanches to break into deeper layers today within our region. It does remain a concern through this week as more snow is forecasted. Be aware that as we get more snow, the stress increases and the likelihood of the avalanches becoming deeper and more destructive increases.
Outside forecast area
We’ve been getting a lot of information for Hatcher Pass over the last week following the fatal avalanche
on Saturday. The take-home message that needs to be passed on: avalanches happened on numerous occasions before and after the fatal event. There is ample visual evidence to show that conditions are dangerous. The conditions are probably not improving very quickly given the character of the weakness. The avalanche conditions are more dangerous in Hatcher right now than in the Chugach and Kenai mountains.
Encyclopedia of avalanche terms.
The weak low pressure in the Gulf of Alaska is still bringing some moisture through Prince William Sound and into Turnagain arm. The intensity has dropped considerably since yesterday, but small amounts of snow are still in the forecast today. Wind yesterday gusted into the upper 20s at some weather stations. Up to 2 inches of snow today on top of the 6-9 inches from yesterday. Wind will be light and temperatures in the 20s in the alpine.
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 FRI MAR 25 2011
.TODAY…NUMEROUS SNOW SHOWERS. SNOW ACCUMULATION UP TO 2 INCHES.
HIGHS IN THE MID TO UPPER 30S. LIGHT WINDS.
.TONIGHT…NUMEROUS SNOW SHOWERS IN THE EVENING…THEN SCATTERED
SNOW SHOWERS AFTER MIDNIGHT. SNOW ACCUMULATION UP TO 1 INCH. LOWS
IN THE MID 20S TO LOWER 30S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR
.SATURDAY…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS IN
THE MID TO UPPER 30S. LIGHT WINDS EXCEPT NORTH 10 MPH NEAR SEWARD.
.SATURDAY NIGHT…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. LOWS
15 TO 25…COOLEST INLAND. LIGHT WINDS EXCEPT NORTH 10 TO 15 MPH
.SUNDAY…MOSTLY CLOUDY. SCATTERED SNOW SHOWERS IN THE MORNING…
THEN SCATTERED SNOW AND RAIN SHOWERS IN THE AFTERNOON. HIGHS IN THE
MID 30S TO MID 40S. LIGHT WINDS EXCEPT NORTH 15 MPH NEAR SEWARD.
.SUNDAY NIGHT…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. LOWS
IN THE 20S.
.MONDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW AND RAIN. HIGHS IN
.MONDAY NIGHT…CLOUDY WITH A CHANCE OF SNOW. LOWS 15 TO 25.
.TUESDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW AND RAIN. HIGHS IN
TEMPERATURE / PRECIPITATION
SEWARD 38 27 40 / 60 60 50
GIRDWOOD 36 26 36 / 80 50 30
WEATHER STATION SUMMARY for Turnagain Pass:
-3800′ Sunburst Wx Station-
Temperature 21. Light wind from the ENE.
-2600′ Seattle Ridge Wx Station-
24 degrees. Light wind from the East.
-1800′ Center Ridge Wx Station-
27 degrees. 4 inches new snow and 0.4 inches water recorded yesterday.