Turnagain Pass Avalanche Forecast

Good morning backcountry travelers this is Carl Skustad with the Chugach National Forest Avalanche Information Center on Saturday April 3rd, 2010 at 7 am. 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

A Big thanks to the Friends Group,the Alyeska Resort, and all of you that volunteered and participated in last weekends Telepalooza AK fundraiser. Your support makes this advisory possible.

Skookum Valley and Skookum Glacier are closed to motorized vehicles (snowmachines, helicopters, ATVs) except for subsistence uses.. This closure is directed in the current Chugach National Forest Land and Resource Management Plan. Placer River Drainage remains open for motorized use to Spencer Glacier.

WEATHER ROUNDUP

Lisa just tallied the March weather chart and came up with a nice snowy outcome. 152″ of snowfall, 15″ snow water equivalent and 5 storms over 15″. This puts our Turnagain snowpack at roughly 124% of normal.

As for current weather, no new snow in the past 48 hours and limited chance of precip today. The satellite images show scattered cloud cover and the radar is mostly clear. Winds have been light with moderate gusts on Sunburst yesterday afternoon. Temperatures peaked yesterday at 5pm reaching 45 at sea level and 34 at 3200 ft on Max’s. Sunburst Ridge reached 28 deg F.

AVALANCHE DISCUSSION

Today’s avalanche danger is MODERATE with pockets of CONSIDERABLE this afternoon due to a complex snowpack consisting of buried weak layers of surface hoar and suncrusts. Afternoon sun and buried surface hoar will be the primary avalanche hazards today.

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully. Natural avalanche unlikely this morning, natural avalanches possible this afternnon. Human triggered avalanches possible and likely in pocketed areas. If an avalanche is triggered it could go very large. 3 ft of new snow in the last week on top of buried surface hoar will promote large propagation and dangerous sized avalanches.

El Presidente Repetto found a yellow light snowpack on Sunburst Mt yesterday (CT22Q2) under 41 inches of snow. That weak layer is one week old and consists of a suncrust on south aspects and surface hoar on north aspects.

Areas where one could likely trigger an avalanche today exist on steep rollovers or hanging snow fields near ridgetops. Wind slabs will be present in the alpine. All aspects have either buried surface hoar (north aspects) or buried sun crusts (south aspects). These weak layers have cross over and duplication on east and west aspects.

The sun is a critical “watch out” situation this time of year. Avalanche danger increases quickly during periods of rapid warming temperatures and direct sunlight.

CNFAIC Staff than sunny slopes, the buried surface hoar is a serious concern today. We did record some natural avalanche activity that occured 24 to 48 hours ago. The SW aspects of Tin Can Common, Sunburst, and Magnum. The N aspects of Tin Can “Todd”, Petes South, and Petes Peak. Many point release and loose snow avalanches were noticed yesterday afternoon.

Terrain management is the key today. Keep your slope angles below 35 degrees. AVOID traveling on sunny slopes IF the sun comes out and get out of avalanche terrain immediately if it does. Remember that most of the avalanches that failed on the surface hoar have occurred on northern aspects.

Glide cracks are secondary concern today. These crevasse like features are those cracks that go all the way to the ground. Avoid traveling underneath these cracks. A full depth climax avalanche occurred on lower Goat Ridge in Girdwood Valley on 3/30/2010.

WEATHER FORECAST (National Weather Service)

WESTERN PRINCE WILLIAM SOUND-

INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS

500 AM AKDT SAT APR 3 2010

.TODAY…MOSTLY CLOUDY. HIGHS IN THE LOWER TO MID 40S. LIGHT

WINDS.

.TONIGHT…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. LOWS IN THE

UPPER 20S TO MID 30S. VARIABLE WIND TO 10 MPH.

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

3 INCHES ABOVE 1000 FT ELEVATION. HIGHS IN THE MID 30S TO MID 40S.

EAST WIND 20 TO 30 MPH.

.SUNDAY NIGHT…NUMEROUS SNOW SHOWERS. LOWS IN THE MID 20S TO

LOWER 30S. EAST WIND 20 TO 35 MPH.

.MONDAY…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. HIGHS IN THE

MID 30S TO LOWER 40S. EAST WIND 10 TO 25 MPH.

.MONDAY NIGHT…MOSTLY CLOUDY WITH SCATTERED SNOW SHOWERS. LOWS

25 TO 35.

TEMPERATURE / PRECIPITATION

SEWARD 45 33 44 / 0 50 60

GIRDWOOD 44 27 43 / 0 30 40

WEATHER STATION SUMMARY for last 24 hours at TURNAGAIN PASS

3800�-Sunburst Wx Station

Temp (5am): 25 (no change from yesterday morning)

Winds: current east winds are light, yesterday saw moderate easterly winds.

2600�-Seattle Ridge Wx Station

Temp (5am): 26 (no change)

Winds: current southwest winds are light, yesterday saw light southeast winds.

1800�-Center Ridge Wx Station

Temp (5am): 27(1 degrees warmer than yesterday morning)

Precip: 0 new snow, total snowpack is 141 after 5 inches of settlement.

Thanks for checking today’s avalanche advisory. Lisa will update this advisory tomorrow Sunday April 4th, 2010 by 0700.