Thread by @Lidsville

This is what Vern Ruskin, the experienced BC Hydro dam engineer who spoke against #SiteC at the 2017 BCUC review, was warning about: a landslide wave. He said the weak banks of #SiteC's reservoir could slide, creating a wave that could overtop/collapse the earthfill dam. #bcpoli

https://twitter.com/Mo_Heidarzadeh/status/1278802466847494144

..and here's ABC News' much better video of the same landslide and resulting wave in Myanmar. It's a good demonstration of just how much force these collapses could place on an earthfill dam built on unstable substrate. Like at #SiteC. #bcpoli

https://twitter.com/ABC/status/1278775725496184834

A famous example of a landslide into a reservoir creating a wave that overtopped the dam is the Vajont Dam failure in 1963, N. of Venice, Italy. It happened when the reservoir was first being filled, creating a steep 820-foot high wave. en.wikipedia.org/wiki/Vajont_Dam #SiteC

The whole history of the Vajont dam builders ignoring increasing warnings about instability in the area is gripping - great Wikipedia entry. Some of the same elements as #SiteC - local seismic tremors, signs of landslides... and yet they kept filling the reservoir anyway.

"The flooding in the Piave Valley from the huge wave [that overtopped Vajont Dam] destroyed villages of Longarone, Pirago, Rivalta, Villanova & Faè, killing ~2000 people & turning the land below the dam into a flat plain of mud with an impact crater 200 ft deep & 260 ft wide"

(Sorry to have rewritten those last 3 tweets, but correction: it was technically a dam failure not a dam collapse. Valjont dam is still there, just out of commission. Some engineers worry that they could get #SiteC built but problems will arise when its reservoir fills.)

..Here's another one: "Severe landslide causes huge waves in a SW China reservoir." With the huge atmospheric rivers and heavier rains we're seeing with climate change, these landslides will likely occur more often. #SiteC #MuskratFalls

As a result of this thread I just heard from my friend @elvy_delbianco who reports that he lost family in the village of Longarone in the 1963 Vajont Dam landslide disaster, and that his mother's cousin had to go to Longarone to claim his daughter's body. Tragic.

"The [Vajont dam failure] trial ... resulted in lenient sentencing for a handful of the SADE and ENEL engineers. One SADE engineer (Mario Pancini) committed suicide in 1968. The government never sued SADE for damage compensation." en.wikipedia.org/wiki/Vajont_Da…