Analysis of the Durrand Glacier Avalanche Accident

Durrand Avalanche Report page 11
5. One of the skiers reported that the group had to cross debris left by a recent avalanche on
the ski tour up to Swiss Meadows. Such a slide would carry anyone trapped in it over
bluffs or through gullies, and then into the narrow valley of Cairns Creek.
Fig. 11: The south face of Tumbledown Mountain in early winter. On their way up to Swiss
Meadows, the 21 ski tourers crossed almost the entire slope below the bottom of this
picture. The overall slope of this face is between about 38° and 40°.
6. From Swiss Meadows, the touring group continued up through relatively gently sloping and
open terrain at the base of the steeper slopes that go up to the long west ridge of
Tumbledown Mountain. The ascending route was so close to the base of the slope that it
was subsequently overrun by the avalanches that occurred later that day.
7. At about 2240 metres, the lead group took a rest break near the base of a shallow gully (the
La Traviata couloir) that goes up to the west ridge of Tumbledown Mountain. Apparently,
the objective up to this point had been to tour up to Fronalp Peak, a small 2500 m high
summit near the west end of the Tumbledown west ridge. At this juncture, however, Ruedi
Beglinger decided to go up the La Traviata couloir instead.
J. The La Traviata couloir
1. The La Traviata couloir is a trough-like feature that starts on flat-lying glacial till deposits
located at about 2300 m elevation. The base of the couloir consists of a concave talus
apron that is about 71 metres long, and is sloped at an average angle of about 27°. Above
this, the slope is steeper and more uniform and consists of colluvial deposits (scree) that go
up for 204 metres at an angle of about 36°, and then an additional 36 metres at an average
angle of about 37°, to a convex roll-over (see Appendix 1; attached).
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