Detailed Accident Report

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Date: 2003-04-26
Submitted By: M Muse-Meyer - Region 5 - USDAFS
Place: Charity Valley in Alpine County
State: CA
Country: USA
Fatalities: 1
Summary: 1 snowmobiler caught, buried, and killed

***OFFICIAL REPORT***

Submitted by David Beck & Rick Newberry

Sierra Ski Touring

huskyx@nanosecond.co

Site analysis of the avalanche death of Saturday, April 26, 2003

The avalanche location, from the USGS 7.5' CARSON PASS, ALPINE COUNTY, CALIFORNIA QUADRANGLE, is N 38 40 10, W 119 57 22

The site is on the northern slope of the Forestdale Divide about 0.7 Kilometer south of Forestdale Creek. The elevation of the crown is approximately 8,200 feet.

The easiest access is from the Red Lake (Upper Blue Lake) Road bridge over Forestdale Creek. Follow a true azimuth of 147 degrees for 1.1 kilometers

The local geology consists of ancient eroded mudflows, with some cliff outcrops, which create wide, open and smooth slopes ideal for skiers and snowmobilers. Many of the snowmobiles that we observed on our way to and from the site carried snowboards.

The avalanche was located in a steep bowl on the leeward or north side of a large bench. The main Sierra Crest is to the northwest and a thousand feet higher, Forestdale Creek is about eleven hundred feet below the avalanche.

The crown elevation was measured at 8,200 feet. The Avalanche ran less than 200 vertical feet. Starting zone aspect was from north to northeast.

We did not reach the site until Wednesday April 30 a day after it had snowed a foot. Since the crown was located on a 50 degree slope we didn't think it safe to dig a pit.

It was a low crown located in the midst of a 50 degree 100 foot high slope in the east half of the north facing bowl. The bowl has an outward bulge in the middle of it, the slide occurred to the east, right side looking downhill, of the bulge

The crown, which was drifted in, was probably 7 feet deep* and 200 feet wide.

While there was an exposed bare rock out crop on the north side of the lower track most of the snow in the upper track was over 10 feet deep. We could not reach the ground in the track with a 10 foot probe. The bed surface did not get near the ground.

The debris was triangular shaped, 200 feet wide at the top under the crown, tapering to a point about 300 feet from the crown, The deepest part of the debris was about 8 feet. The debris consisted of numerous four to five foot thick broken hard slabs. The victim was located 30 feet up from the point of the debris. He was buried 5 feet deep 15 feet downhill from his snowmobile*.He was only four feet from the western side of the debris*. One of the snowmobile skis was above the snow.* The debris came to rest on a 10 degree slope on the first flat area on the track. Down slope trees indicate that there have been much bigger avalanches in the past. The alpha angle, from the debris toe to crown top, was 25 degrees.

There was no indication of any faceted or weak layers or other avalanche sign. However, photos of the site taken by the rescue party show a narrow patch bare ground about 20 feet below the crown. There may have faceted snow in the steepest part of the starting zone Pit data and several rumored partial burials in March show a pack weakness. We will get pit data when the snow stabilizes.

The avalanche was a direct action HS-3-A (snowmobile) that the victim probably triggered himself. The avalanche occurred within a few days of a snowfall of at least a foot; the new wind drifted snow released before it had time to stabilize. The trigger zone is in a very steep high loading area that is often likely a cornice. There may be a cliff under the starting zone. There were many adjacent 40 degree slopes, which did not slide.

Since it was a relatively small avalanche the victim would have been likely saved if his party had had training, beacons and digging tools.

Information is from our direct observations or the *Alpine County SAR rescue party Tools: Suunto inclinometer, Suunto altimeter watch, Brunton compass, BCA probe

David Beck

Rick Newberry

Sierra Ski Touring

***MEDIA REPORTS***

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Sierra avalanche kills Nevada snowmobiler

Associated Press

4/27/2003 01:55 pm

A snowmobiler was killed in an avalanche in a remote area of the Sierra Nevada south of Lake Tahoe, authorities said.

Louis Magnotti, 43, of Zephyr Cove, Nev., was buried by the avalanche Saturday afternoon while snowmobiling with friends near Charity Valley in Alpine County.

He was dead when rescuers reached him late Saturday night, sheriff's deputies said. The other snowmobilers escaped injury.

The avalanche was 500 feet wide and 1,000 feet long. Magnotti was swept down 600 feet from where he was last seen and found trapped under 5 feet of snow.

Witnesses said he vanished in a cloud of boiling snow. Witnesses searched for him for 45 minutes without success.

The sheriff's office launched a search after being contacted at about 6:45 p.m. About 40 volunteers assisted in the search.

The area along Blue Lakes Road east of Carson Pass is popular with snowmobilers.

The avalanche occurred after another powerful spring storm dumped up to 20 inches of snow and left some Tahoe ski resorts with record April snowfall.

The U.S. Forest Service last week issued an avalanche warning for the east slopes of the Sierra between Sonora and Yuba passes.

The warning was issued at the moderate level, the second lowest of five categories. It urges backcountry users to be cautious around snow-covered open slopes and gullies.

Squaw Valley USA ski resort just north of Tahoe has reported 10 feet of snow from a string of April storms.

Copyright ? 2002 The Reno Gazette-Journal

Sierra avalanche kills Nevada snowmobiler

Associated Press

ASSOCIATED PRESS

4/27/2003 10:11 pm

MARKLEEVILLE, Calif. ? A Nevada snowmobiler was killed in an avalanche in a remote

area of the Sierra Nevada south of Lake Tahoe, authorities said.

Louis Magnotti, 43, of Zephyr Cove was buried by the avalanche Saturday afternoon while

snowmobiling with friends near Charity Valley in Alpine County.

He was dead when rescuers reached him late Saturday night, sheriff?s deputies said. The other

snowmobilers escaped injury.

The avalanche was 500 feet wide and 1,000 feet long. Magnotti was swept down 600 feet from

where he was last seen and found trapped under 5 feet of snow.

Witnesses said he vanished in a cloud of roiling snow. Witnesses searched for him for 45 minutes

without success.

The sheriff?s office launched a search after being contacted at about 6:45 p.m. About 40

volunteers assisted in the search.

The area along Blue Lakes Road east of Carson Pass is popular with snowmobilers.

The avalanche occurred after another powerful spring storm dumped up to 20 inches of snow

and left some Tahoe ski resorts with record April snowfall.

The U.S. Forest Service last week issued an avalanche warning for the east slopes of the Sierra

between Sonora and Yuba passes.

The warning was issued at the moderate level, the second lowest of five categories. It urges

backcountry users to be cautious around snow-covered open slopes and gullies.

Squaw Valley USA ski resort just north of Tahoe has reported 10 feet of snow from a string of April storms.

Copyright ? 2002 The Reno Gazette-Journal