Turnagain Pass Avalanche Forecast

Good morning backcountry travelers. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Monday, March 21th 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).

ANNOUNCEMENTS

Outside our forecasting zone:

In the Hatcher Pass area on Saturday a human triggered avalanche caught, buried and killed a 65 year old skier. This is the first avalanche fatality in Alaska this year. Our condolences to the individual’s family and friends.

BOTTOM LINE

The avalanche danger remains at LOW. In the slight chance that we receive over 2” of new snow the danger will rise for fresh wind slabs on leeward slopes. CNFAIC Staffwise, normal caution remains such as triggering wet sluffs in mid to low elevations or an old wind slab in steep rocky terrain.

AVALANCHE DISCUSSION

It seems there is not enough snow on the way to impact avalanche conditions for Turnagain Arm. Therefore, once again, regular backcountry hazards exist such as popping out an old wind slab in extreme terrain. Mid to lower elevations, especially south of Turnagain Pass, could possibly see some rain which would increase any wet sluff potential associated with today’s warmer temperatures.

This is an optimistic view for snowfall but, if more than a couple inches fall the hazard will rise for shallow loose new snow and wind slab avalanches. Any new snow will likely bond poorly with the hard surfaces out there now. Winds are forecast to gust into the moderate range which is perfect for forming nice soft sensitive wind slabs.

We keep mentioning an unlikely chance of triggering a larger slide in shallow snow cover areas that fails in the old weak sugary snow near the ground; this is the case again today. It may seem like a broken record but events at Hatcher Pass over the weekend, though outside of our advisory area and in a different mountain range, does illustrate how dangerous a thin snow cover can be. Thin snow generally means weak snow and when a hard slab sits on top it is the perfect set up for large dangerous avalanches. In our neck of the woods, the Summit Lake area is one of the thinnest locations and the slab here has lost much of its continuity and ability to react. However, if our drought ever ends and we get new snow adding weight watch for a reactivation and dramatically increasing danger. Deeper snowpacks such as Turnagain Pass will need more of a load, but again, the weather needs to change first.

Encyclopedia of avalanche terms.

WEATHER ROUNDUP

Sunday mostly sunny skies prevailed again with the easterly winds kicking up to 30mph and temperatures around 20F. Currently, skies are partly cloudy, temperatures in the upper teens and low 20’s and winds are around 10mph gusting to 20mph out of the east. Precipitation is splitting around the Kenai and having a hard time spilling over the mountains from the coast south of us. It seems only snow flurries are likely with a trace accumulating today, more possible to the south of Summit Lake. Southeast winds will remain gusty, near 30mph with temperatures warmer, in the 30’s.

The remainder of the week looks like cloudy skies and scattered snow showers. Currently, forecasted snow accumulations are small (0-2”).

Jon 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-

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKDT MON MAR 21 2011

.TODAY…RAIN AND SNOW LIKELY. SNOW ACCUMULATION UP TO 2 INCHES.

HIGHS IN THE MID 30S TO LOWER 40S. VARIABLE WIND TO 10 MPH EXCEPT

EAST 5 TO 20 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.

.TONIGHT…NUMEROUS SNOW AND RAIN SHOWERS. SNOW ACCUMULATION UP TO 2

INCHES. LOWS IN THE LOWER 20S TO AROUND 30. VARIABLE WIND TO 10 MPH.

.TUESDAY…NUMEROUS SNOW AND RAIN SHOWERS. SNOW ACCUMULATION UP TO

2 INCHES. HIGHS IN THE MID 30S TO LOWER 40S. VARIABLE WIND TO 15 MPH

EXCEPT EAST 10 TO 25 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM.

.TUESDAY NIGHT…SNOW AND RAIN SHOWERS LIKELY. LOWS IN THE 20S.

VARIABLE WIND TO 15 MPH EXCEPT EAST 10 TO 25 MPH THROUGH PORTAGE

VALLEY AND TURNAGAIN ARM.

.WEDNESDAY…SNOW AND RAIN SHOWERS LIKELY. HIGHS IN THE MID 30S TO

LOWER 40S. VARIABLE WIND TO 10 MPH. THROUGH PORTAGE VALLEY AND

TURNAGAIN ARM…EAST WIND 10 TO 25 MPH.

.WEDNESDAY NIGHT…MOSTLY CLOUDY WITH A CHANCE OF SNOW AND RAIN

SHOWERS. LOWS 15 TO 25.

.THURSDAY…MOSTLY CLOUDY WITH A CHANCE OF SNOW AND RAIN. HIGHS

35 TO 45.

TEMPERATURE / PRECIPITATION

SEWARD 39 28 41 / 60 60 60

GIRDWOOD 35 23 35 / 40 50 60

WEATHER STATION SUMMARY for Turnagain Pass:

-3800′ Sunburst Wx Station-

17 degrees. East wind 8mph gusting to 12mph.

-2600′ Seattle Ridge Wx Station-

21 degrees. Southeast wind 14mph gusting to 21mph.

-1800′ Center Ridge Wx Station-

24 degrees. No new snow.