Hope landslide

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The landslide of Hope (Engl. Hope Slide ) occurred on January 9, 1965 in Hope , 135 kilometers east of Vancouver , the largest city in British Columbia , in the extreme southwest of Canada. Hope had been promoted to town shortly before.

The great 1965 landslide near Hope, Canada (2005 photo)
Hope Slide Information Board

The landslide was the largest to date in Canadian history and - although in an almost uninhabited area - cost the lives of four people, two of the victims were never found. It tore off a steep slope (> 45 °) just below a ridge in the Cascade Mountains and poured into a side valley of the Coquihalla River , which flows into the Fraser River about 10 km further at Hope . Local surveys showed that 46 million cubic meters of rock and rubble fell down a slideway that was inclined by about 20 ° under the steep slope and was left in a huge heap 70 meters high and three kilometers long. According to a rule of thumb from Albert Heim , the mass falling on the slideway must have had a speed of over 200 km / h.

The debris avalanche filled a lake (Outram Lake) near the Nicolum River completely and shifted the course of the river. It also rolled over a few miles from Highway 3 (a branch of the newly opened Trans-Canada Highway ) that had to be closed for weeks. However, short-term closures are often necessary in winter and because of minor landslides.

It is not possible to clearly determine whether a small earthquake triggered the landslide. It could also indicate a previous landslide . The rock of the mountainside is old, metamorphic basalt , but with layers of clay minerals and some fault lines. Most geologists assume that the clay was saturated with water from previous weather conditions.

literature

Individual evidence

  1. ↑ corresponds to a rock volume of 50 × 50 × 185 meters
  2. ↑ lock z. B. in February 2008: Coquihalla remains closed, in: Hope Standard, February 14, 2008 ( Memento from March 31, 2008 in the Internet Archive )