Accident: Turnagain

AMRG Mission Summary Feb 23, 2008:

Three male snowmachiners were caught and buried in an avalanche path known as Stock Run #1 in Turnagain Pass late in the day on 2-15-08. One of the buried riders was recovered alive and two were killed. Both deceased subjects were dug out from the debris but were left at the scene due to deteriorating weather, darkness, and the need to transport the injured rider from the scene along with several party members who were suffering from exposure. Victim 1 was placed in a body bag near the toe of the debris and his location marked with an avalanche probe. Victim 2’s body was left on the surface of the debris higher up in the avalanche runout zone. A significant storm cycle ensued in the southcentral Alaska region for the next 8 days, bringing heavy snow and extreme winds and preventing AST from recovering the 2 bodies at the scene. On 2-20-08, approx. 13 friends of the deceased snowmachiners were able to reach the area, locate Victim 1 and retrieve his body. No attempt was made to locate or recover Victim 2. AST requested the assistance of AMRG, ASARD, and DOT to find and recover Victim 2 once the weather cleared allowing avalanche mitigate and searching in the area to begin.

The Alaska Mountain Rescue Group and Alaska Search and Rescue Dogs returned on 2-23-08, the first “blue weather day” after the accident, to locate the body of Victim 2. The location of Victim 2 was only generally known as an approximate direction and distance from a GPS coordinate taken at the location of the first body that had been recovered earlier. Approximately 8-10 feet of new snow had fallen during the previous week of storms in the area completely covering all of the old debris and any surface clues. Avalanche control work was conducted by DOT via aerial bombing from Helo-1 in the basin to eliminate the potential for a new slide to impacting the search area. Approximately 6 double charges and 2 single charges were placed in the basin, generating one significant avalanche(R3) and releasing one additional pocket. DOT and AMRG personnel determined that the area could be safely searched following control work.

A systematic search of the new debris with dogs and beacon searchers was conducted to locate transmitting beacons drop in what was thought to be the general area of Victim 2s body. The beacon search resulted in finding one of the “marker” beacons as well as a gear cache of 5 backpacks and one digital camera bag belonging to members of the original party caught in the avalanche on 2-15-08. A transmitting OrtovoxM-2 beacon was still transmitting in one of the backpacks which were located approximately 8 to 11 feet below the surface. Onsite discussion with Trooper H. Peterson (who was at the scene of the original avalanche) was used to confirm the likely area of Victim 2’s body—which turned out to be to the west of the new debris created by avalanche control work. A dog search of the area resulted in one area of interest that was probed extensively with no results. A simultaneous, closely-spaced RECCO search of the same area resulted in two distinct RECCO hits within 8′ of each other around 1400.

The search pattern consisted of lateral passes across the slope spaced at 5′ intervals with the RECCO pointed straight down and slowly swung four times back and forth across a 5′ span as near to the snow as possible, at maximum receive gain, with different antenna polarizations on each swing. After approximately one hour of searching a very weak signal was detected. It was pointed straight down and was stronger if the antenna was touching the surface of the snow. 5 minutes of probing with 12′ and 16′ poles finally established that there was something buried at the location. This probe strike was confirmed to be the body of Victim 2 after considerable digging.

Victim 2 was found lying prone on his back, head downhill under approximately 9 feet of new snow that had fallen in the previous week. His face and torso were covered with what appeared to be a grey sweatshirt. The coordinates of the location of the body were: N 60 49.885′ W 149 10.598′ (WGS84). It was confirmed by passing the RECCO over the body that the object that reflected the RECCO signal was a DTS Tracker avalanche transceiver that was on top of the body in a left front hip pocket. The transceiver switch was in the “off” position having been turned off by the original party (according to Troopers) on 2-15-08. The red ski of a snowmachine was near the right shoulder of Victim 2 and was the likely source of the stronger, second RECCO hit that was noted about 8′ away during the initial search. Victim 2 was completely extricated from the snow, placed in a body bag, and transported to the LZ by 1500 for removal to Anchorage. Transport was delayed until approximately 1800 due to another avalanche accident on the other side of the Seward Highway at Sunburst Mountain (see seperate accident report at cnfaic.org).

***CNFAIC AVALANCHE ADVISORY***

February 15, 2008

Good morning backcountry travelers. This is Carl Skustad with the Chugach National Forest Avalanche Information Center on Friday, February 15th at 7am. This notice will serve as a general backcountry avalanche advisory 5 days a week (Wednesday-Sunday) for the Turnagain Arm area, local variations always occur.

Weather Observations
In past 24 hours:
The Center Ridge weather station at 1800 feet in Turnagain Pass recorded 2 inches new snow as .2 inches of water. Total snowpack depth is 94 inches (2 inches more than yesterday). Two day storm totals are 11 inches in Turnagain Pass and 23 inches at Alyeska. The temperature this morning is 14 degrees F (16 degrees colder than yesterday).

Sunburst weather station at 3800 feet in Turnagain Pass recorded gale force winds over the last two days. Strong NE winds averaging 20-30 mph were steady yesterday. Winds have subsided slightly and are shifting to the SW. Ridgetop temperatures have dropped 12-13 deg F since yesterday.

The radar shows last night’s storm split and traveled up the Cook Inlet to Anchorage and east to Cordova providing us with minimal snowfall but strong winds. The next low is slow on the move but should hit land tomorrow. Its exact tract is uncertain. Moderate snowfall is expected.

Bottom Line (Primary Avalanche Concerns)
The avalanche hazard remains the same as yesterday [CONSIDERABLE]. Today natural avalanches will be possible and human triggered avalanches will be probable on steep slopes.
1. Wind slabs
2. The most recent layer of buried surface hoar that formed over the past two weeks. This weak layer is buried about 16-23 inches deep. This layer is fairly widespread in the Kenai and Chugach Mountains.
3. Two other weak layers of buried surface hoar exist in isolated pockets approximately 3-4 feet down and 4-6 feet down.

Avalanche and Snowpack Discussion (More detailed info…)
The main avalanche concern today will be new storm snow on top of that layer of cold snow and buried surface hoar that formed during the past two weeks of cold sunny weather. We now have warmer denser snow sitting on top of colder lighter snow. This type of snow always needs time to heal before it bonds together. It is always a good reminder that the majority of human-triggered avalanches occur during storms or within 24 hours of a storm; so, extra caution is advised on slopes steeper than 30 degrees today. Another good reminder is that an overwhelming majority of human-triggered avalanches occur on layers of buried surface hoar. That is exactly what we have out there right now. There were several areas where the most recent layer of buried surface hoar formed on top of a firm wind layer. These areas will be likely areas to trigger an avalanche on that particular weak layer of feathery crystals. Poke around with your pole. If you feel a firm bed surface, it will be worth your time to dig down to look for this weak layer on top of that firm surface. If you see a visible layer on the sidewall of your isolated column, or if you discover a clean fast shear on a stability test, then you might have found that dangerous weak layer.
We should approach the mountains with caution and respect today and give this new snow a chance to settle down.

Weather Forecast
WESTERN PRINCE WILLIAM SOUND-
INCLUDING…WHITTIER…SEWARD…GIRDWOOD…MOOSE PASS
630 AM AST FRI FEB 15 2008
.TODAY…SNOW SHOWERS IN THE MORNING MAINLY FROM TURNAGAIN PASS NORTH WITH ADDITIONAL SNOW ACCUMULATION 1 TO 3 INCHES. BECOMING PARTLY CLOUDY IN THE AFTERNOON. HIGHS IN THE MID 20S TO LOWER 30S EXCEPT IN THE MID 20S INLAND. SOUTH TO WEST WIND 15 TO 25 MPH IN THE MORNING BECOMING LIGHT. GUSTS TO 35 MPH THROUGH PORTAGE VALLEY AND TURNAGAIN ARM IN THE MORNING…WITH AREAS OF BLOWING SNOW REDUCING VISIBILITY TO ONE HALF MILE AT TIMES.
.TONIGHT…INCREASING CLOUDS. LOWS IN THE MID TEENS TO LOWER 20S. LIGHT WINDS BECOMING EAST 5 TO 15 MPH AFTER MIDNIGHT. ALONG TURNAGAIN ARM AND THROUGH PORTAGE VALLEY…SOUTHEAST WIND 20 TO 30 MPH AFTER MIDNIGHT.
.SATURDAY…SNOW. SNOW ACCUMULATION 3 TO 6 INCHES. HIGHS IN THE MID 20S TO LOWER 30S. NORTH TO EAST WIND 15 TO 30 MPH EXCEPT SOUTHEAST WIND 25 TO 35 MPH ALONG TURNAGAIN ARM AND THROUGH PORTAGE VALLEY.
.SATURDAY NIGHT…SNOW LIKELY. LOWS IN THE MID 20S TO LOWER 30S. EAST WIND 10 TO 20 MPH.
.SUNDAY…SNOW LIKELY. HIGHS IN THE UPPER 20S TO MID 30S. EAST WIND 10 TO 25 MPH.

TEMPERATURE / PRECIPITATION
SEWARD 25 16 27 / 0 0 80
GIRDWOOD 25 15 25 / 40 0 80

Let us know if you see or hear of any avalanche activity. You can leave a message at 754-2369 or email us by going to our home page at avalanche.org. The next advisory will be on Saturday, February 16th.

**MEDIA REPORTS**

Turnagain Pass avalanche kills 2
SNOWMACHINERS: About 500 to 700 feet of the mountain collapsed.
By MEGAN HOLLAND and CRAIG MEDRED
Anchorage Daily News | mholland@adn.com
Published: February 16th, 2008 12:30 AM

Two snowmachiners died in an avalanche at Turnagain Pass late Friday afternoon, Alaska State Troopers said. Troopers late Friday night identified the victims as Christoph Vonalvensleben, 25, and Jeremy Stark, 27, both of Anchorage. The two were swept up in the slide and buried on a mountain above Seattle Creek north of Turnagain Pass near Mile 68 of the Seward Highway, said trooper spokeswoman Beth Ipsen. She said the victims were in a party of six snowmachiners who were highmarking and inadvertently triggered the avalanche after being out on the mountain for only about 10 minutes. A third man, 38-year-old Andrew Baugh of Girdwood, was partially or fully buried but survived, Ipsen said. The fatalities occurred hours after park officials and avalanche experts warned that 10 inches to a foot of new snow had created treacherous conditions in Southcentral’s mountainous backcountry — especially treacherous because the fresh snow would look great for snowboarding and snowmobiling.

Friends of the victims described them all as longtime Anchorage residents and experienced snowmachiners who often pushed the limits in backcountry. “These guys ride three days a week. They knew the risks,” said Jimmy Blaze, a longtime snowmachiner and friend of the victims who had talked by telephone with other members of the group. “If they had to go, at least they went that way instead of some freak drunk-driving hit on the highway on the way home,” he said. “They were doing what they love.” Blaze, who said he often snowmachines in Turnagain Pass, said the area of Friday’s avalanche is known to be slide-prone. Ipsen said an initial 911 call came in at 4:45 p.m. reporting the avalanche and that the slide may have swept over some people, Ipsen said. There were about half a dozen friends skiing two bowls back from the parking lot when the avalanche occurred. Ipsen said about 500 to 700 feet of the mountain collapsed, leaving a swath of debris 200 feet wide. Two other people were caught up in the slide but not buried. All members of the snowmachining group reportedly had avalanche beacons, Ipsen said. The other snowmachiners found the trapped people about 45 minutes after the slide, Ipsen said. They were dead. A trooper helicopter flew to the scene Friday evening. The bodies were not recovered because conditions on the mountain were too risky, Ipsen said. Troopers will attempt to recover them this morning at first light. “The area is a very popular area. Usually more experienced snowmachiners go out there,” Ipsen said. Conditions remain dangerous, Ipsen said.

Even before the latest snowfall, said Debra McGhan, executive director of the North America Outdoor Institute in Wasilla, conditions in the area were getting dicey, with Turnagain Pass and Hatcher Pass especially problematic. “On Feb. 1,” she reported, the institute’s Dan Dryden “counted over 10 recent avalanches in Hatcher Pass. The avalanches were on all aspects — north, south, east and west. He skied up the west ridge of Microdot (Mountain) and encountered shooting cracks, a clear marker of snowpack instability. He reported hearing whoomping of a collapsing weak layer at approximately 3,500 feet.” Upon digging a snow pit, Dryden found the situation worse. There were multiple layers of dense, compact snow sitting on layers of weak, unconsolidated snow. These are prime conditions for creating the kinds of avalanches that send automobile-size chunks of slab roaring downhill. “(And) now we have several new inches of snow as the icing on top of this mixture,” McGhan said in an e-mail. “In layman terms, this is a lasagna recipe for avalanche. The (loose) depth hoar acts like ball bearings, and all it takes is a simple trigger like … a snowboarder, skier or snowmachine to rip it loose and put everything in its path in peril.” McGhan said anyone planning to recreate this weekend needs to be especially careful. She noted there have been more than 50 avalanche victims in the state in the past decade.

The Chugach National Forest Avalanche Center is warning not only of the risks of human-triggered avalanches but of dangers of people being caught in runout areas by naturally occurring avalanches. The Turnagain Pass area has the same layer-cake problem that Hatcher Pass has. Wind slabs, Chugach avalanche officials report, have formed “over the most recent layer of buried surface hoar that formed over the past two weeks (of cold). The weak layer is buried about 16 to 23 inches deep. This layer is fairly widespread in the Kenai and Chugach mountains. Two other weak layers of buried surface hoar exist in isolated pockets approximately three to four feet down and four to six feet down.” An avalanche triggered at such depths would likely be massive, but even a slide going only a foot deep can easily bury and kill someone. Closer to Anchorage, conditions are equally dangerous in Chugach State Park, officials said.