Incidents historiques

Résumé de l'incident

Date
2020-11-28
Location
Pine Pass - Bijou Falls
Location Description
Approximately 20 km east of Mackenzie, BC
Province
BC
Coordinates
55.29895 °, -122.72537 °
Elevation
1680 m
Activity
Snowmobiling
Involvement
1
Injury
0
Fatality
1
Description
Several days of stormy weather with warm temperatures and winds dropped significant amounts of new snow in the days leading up to the accident. Skies broke and temperatures cooled on the morning of November 28th and SW winds strong enough to move new snow were recorded in the region. Two snowmobilers were riding in the Bijou Falls riding area towards the east side in a portion of terrain overlooking highway 97. One rider climbed high on the slope gaining a wind-exposed ridge above a rock band. The rider triggered a large avalanche, approximately 800 metres wide by 400 metres long. The crown was 55cm deep on the steep, rocky, windswept roll where the avalanche was triggered, but significantly more snow was involved at lower elevations where the snowpack was sheltered from wind and much deeper. The bed surface was a crust that formed in early November and the suspected failure layer was faceted grains on the crust. The snowmobiler was caught in the avalanche and buried in a terrain trap near the base of the slide. Their partner, who was watching from below and was not caught by the avalanche, performed companion rescue to locate and dig out the victim. The buried person did not survive.

Avalanches

Date/HeureTailleTypeDéclencheurAltitudeVersantLargeur de la plaqueÉpaisseur de la plaque
3.0SMa1680 mNE800 m55 cm

Weather

Température actuelleTempérature maximaleTempérature minimaleTendance 24hVitesse du ventDirection du ventCondition du cielType et intensité des précipitations
---RL--NIL

Commentaire météo: Weather recordings were taken from Link Creek Weather station (730 m) approximately 10 km north of incident location.

Snowpack

Manteau neigeuxNeige 24 hrsNeige de tempêteDate de la tempête
160 cm---

Commentaire sur le manteau neigeux: 100 cm 1F+ to P resistance snow overlay a thick (20 cm) weaker layer (4F resistance) resting on a crust (I resistance). Compression tests yielded sudden planar failures down 110 cm in the easy/moderate range (one test gave 7 taps, one test gave 11 taps). In the snow profile, the snow failed on facets above the crust, which is consistent with the failure plane of the avalanche. The profile location was adjacent to the avalanche flank.

Documents

Date du documentTitreSource
2020-12-10Google Earth image, annotatedAvalanche CanadaVue
2020-11-29Profile by SAR teamPG SARVue