Detailed Accident Report

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Date: 2001-02-24
Submitted By: Doug Chabot GNFAC
Place: Absorka/Beartooth Range
State: MT
Country: USA
Summary: Snomobiler Burial; Located by Transceiver

This is from Scott's Advisories. He'll post a more detailed account of

the avalanche sometime this week.

2/25/01 "...An example is an avalanche burial that occurred yesterday in

the Absorka/Beartooth Range up at the head end of the Boulder River. A

21-year-old snowmobiler was wrestling his stuck snowmobile on a small

slope. In the process of getting his sled turned he triggered an

avalanche that completely buried him. The young man was located with an

avalanche transceiver and extricated in approximately 20 minutes. He was

resuscitated on scene and transported by Life Flight helicopter to

Billings were he is in stable condition. I?m going to head over and look

at the avalanche today and I?ll give you more details tomorrow. We have

received reports of 13 human triggered avalanches on the Gallatin

National Forest since the 1st of February. These avalanches are the

result of variable avalanche conditions which are hard to predict and I

continue to urge you to use caution as you go about your steep slope

recreation."

2/26/01 "...The avalanche rescue that took place over on the Boulder

River points out some good solid rescue skills we all can learn from.

The young snowmobiler was the only one on the slope and no one went to

help him get unstuck. Consequently, only one person was buried. The

party all had avalanche transceivers and knew how to use them. Knowing

how to use their transceivers paid off big because they located the

buried mans general position quickly. The parties located the exact

position with an avalanche probe pole and begin digging through 6 feet

of rock hard debris. It took two shovelers more then 15 minutes to get

an airway to the buried man and, even with additional shovels, it took

more then an hour to fully extricate him. Had the party not had

transceivers, shovels, and probes - and the skills to use them fast and

effectively - this story would not have had a happy ending."

Doug Chabot, Gallatin National Forest Avalanche Center

ONE SNOWMOBILER CAUGHT AND BURIED IN MONTANA AVALANCHE

A 20-year-old snowmobiler was riding with a large group during the

annual Sweet Grass Recreation Association?s poker run. This event was

held Saturday, February 24th in the Independence area at the head of the

Boulder River located south of Big Timber. The young man was

high-marking a steep, narrow, north-facing chute when he became stuck.

Attempting to free his snowmobile he triggered an avalanche

approximately 200 feet above him measuring 500 feet wide, 2 ? 3 feet

deep and 800 feet vertical. The slope angle of the trigger point was 38

degrees while the angle at the crown ranged from 36 degrees to 38

degrees. The US classification for this slide is HS-3-AV-O.

During the month of November, unseasonably cold temperatures faceted

approximately 1 foot of snow that was on the ground at the time. New

snow on top of these facets resulted in wide spread avalanching

throughout Montana in the months of December and January. In most

locations these facets have strengthened, yet remains a factor in

isolated avalanches where the snowpack is thin. In the Independence area

of the Boulder the seasonal snowpack is less then three feet deep and

the facets remain extremely well developed. Approximately 1 foot of new

snow fell during the previous two weeks and strong southwest winds had

loaded the top of the bowl and cross-loaded the chute. This region is

outside the advisory area for the Gallatin National Forest Avalanche

Center but the avalanche danger for that day was Moderate on all slopes

steeper then 35 degrees and Low elsewhere.

The majority of the avalanche was funneled down the chute and the victim

had his back to the avalanche unaware of the slide. He was caught and

carried 600 vertical feet to the toe of the debris where he was buried 5

? 6 feet deep. The victim?s father, along with several other members of

the party witnessed the avalanche and responded immediately. They

located the victim?s general location with an avalanche transceiver and

used an avalanche probe to pinpoint his exact position. Two members of

the party used shovels to partially uncover the victim who was

unconscious and not breathing. He was given mouth-to-mouth resuscitation

and resumed breathing on his own after a few breaths. Total time of

burial was between 15 and 20 minutes. A Life Flight helicopter was

called by cell phone and the victim was flown to a Billings hospital

where he was released the next day with no major injuries.

The results of our investigation conclude that the slide was triggered

on the faceted layer near the ground in the chute and the failure

propagated uphill to the wind loaded ridge top. Stability tests near the

crown face indicate the snowpack in this area will remain weak for the

remainder of the winter.

For more information you may contact me at 406-587-6984, or at

sschmidt@fs.fed.us.

Scott Schmidt, Avalanche Specialist, Gallatin National Forest Avalanche

Center