Detailed Accident Report

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Date: 2000-03-22
Submitted By: STAN BONES; Glacier Avalanche Center
Place: Gildart Peak, Swan Range in NW Montana
State: MT
Country: USA
Fatalities: 1
Summary: 1 snowmobiler caught, not buried and killed

Today Wednesday, 3-22-00, a 35 year old male snowmobiler was killed in an

avalanche on Gildart Peak (SW 1/4, Sec 16, T24N, R16W, PMM) in the Swan

Range of Northwestern Montana. The site is approximately 28 air miles

southwest of Kalispell, Montana and only about two miles north of where

another young snowmobiler was killed two years ago.

A party of seven riders mostly from Polson, Montana had spent the day

riding high on the crest of the Swan Range (elevation 7000-7500'). They

had accessed the area via Soup Creek and Inspiration Pass to the west and

south.

At approximately 2:00 PM when the victim was highpointing an open slope on

a southeast aspect, a slab avalanche released above him. He was carried by the

flowing snow at a high rate of speed, smashed into a tree in the runout

zone, and died of a massive head injury. The victim was not buried by the

avalanche, was recovered on the surface of the snow, and if it had not been

for the tree, probably would have escaped the slide uninjured. All members

of the party were carrying avalanche transceivers, probes, and shovels.

After the incident one member of the party alerted authorities by cell

phone while others attempted CPR on the victim. Kalispell Medical Center's

ALERT helicopter was dispatched and arrived on scene approximately 45

minutes after the avalanche and pronounced the victim dead soon after.

The avalanche was estimated to be 300 ft wide, 500 ft long slope distance,

and having a crown fracture of near 3 ft. The crown was just below the

crest ridge. The releasing slope was estimated to be 32-40 degrees and

facing southeast. The avalanche debris was dry to wet, hard blocks.

This area had received considerable new snow over the previous 11 days. At

the Noisy Basin SNOTEL approximately 26 miles north on the Swan crest, 4.7"

of snow water equivalent was recorded between Saturday, March 11th and

Sunday, March 19th. This translates into approx. 20" of new snowfall.

During that time period moderately strong winds had also been experienced.

The Swan Lake MDOT weather station in the valley at Swan Lake recorded on

Sunday 10-17 MPH winds mostly from the west and northwest, with gusts up to

21 MPH. Mountain temperatures at 6400 ft had generally been cool up to the

day of the incident. Daytime highs at Noisy SNOTEL were just warming to

freezing, while lows were mostly in the high teens and low 20's F. These

were giving daily average temperatures near 25 F. On the day of the

incident however, the air temperature soared to 41 F at the Noisy Basin

SNOTEL at 2:00 PM.

The avalanche advisory issued by Glacier Country Avalanche Center Tuesday

morning, March 21st rated the dry snow avalanche danger at MODERATE on

recently wind loaded slopes and the wet snow danger as CONSIDERABLE.

It is believed that this incident can be blamed upon heavy new snowfall

often accompanied by wind, rapidly warming temperatures, and triggering by

the combined weight of a snow machine and rider. It is unfortunate that a

tree stood in the way in the runout. If that had not been the case, the

party would have undoubtedly only had a wild story to tell friends and

family when they returned home. It's often only a fine line that separates

existence from oblivion, happiness from despair and grief.

This incident highlights the explosion that is occurring in mountainous,

backcountry use in the winter. Previous incidents like this in

Northwestern Montana have almost exclusively happened on weekends. An

increasing population with more free time is making any day of the week a

potential event. It also highlights how users, especially snowmobilers,

are pushing farther and higher into avalanche terrain.

Stan Bones

Glacier Country Avalanche Center