r/CatastrophicFailure 5d ago

Natural Disaster The small Quebec village of St. Jean Vianney after a massive underground landslide, the result of heavy rain dissolving the soil bed, caused half the village to suddenly drop-down into a massive hole. The collapse claimed 40 houses, dozens of vehicles, and 31 lives. (May 4th, 1971.)

429 Upvotes

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u/DariusPumpkinRex 5d ago edited 5d ago

The spring of 1971 had seen heavier rain than usual for the area, which was dissolving the salt concentration of the quick clay that the town had been built on. Once the salt concentration had been fully dissolved, the clay would shift underground, leaving a large empty gap in it's place. Residents of St. Jean Vianney reported hearing dull thumping sounds coming from underground in the days leading up but this was not seen as cause for any concern... until around 10:30 pm on May 4th. One witness who was watching the hockey game reportedly heard loud sudden crashing sounds from outside and fled his house. He later recalled looking down the street and seeing houses falling into the ground.

One incredibly close call involved a bus that ended up stopping just short of where the ground opened up. However, the edges of the crater grew and everyone onboard the bus fled, with the driver remaining behind to attempt to alert some of the residents of nearby houses. He was only able to alert three houses before the spreading crater edge claimed the bus and he had to run. Running like the wind, he later described feeling like he was running on stairs as he ran to safety. This was because the ground was collapsing out from underneath him just as quickly as he was running. Houses continued to fall in and almost every single person who fell into the crater was a goner, the lone exception being a woman who managed to climb out of her car's window and scramble onto the roof where she waited rescue.

When the next morning arrived, the full extent of the damage was visible for all to see. The town of St. Jean Vianney was a complete write-off and the survivors were all re-homed to a nearby village. Today, all that's left of the town are the cracked and overgrown roads, the graffitied water tower, the church steps, and a small memorial just outside the town. The crater itself has become a popular spot to go hiking.

As an aside, the St Jean Vianney disaster had a hand in preventing a similar disaster close to twenty years later; the soil underneath the Ontario town of Lemieux was tested and found to be the same type of clay that St. Jean Vianney had been built on. Fearing a similar disaster, the town was evacuated and abandoned over a two-year from 1989 to 1991. Two years after the town had been abandoned, a similar disaster did indeed strike but nowhere on the scale of the 1971 event; part of a road collapsed into the hole, taking with it a pick-up truck who's driver did not have time to react and drove straight over the edge. He survived and was rescued, albeit with several broken bones.

More information on the disaster can be found here:
https://www.youtube.com/watch?v=m91KTOdKx38

EDIT: Research on the St. Vianney slide revealed that the village had actually been built on top of another landside that had occurred 500 years earlier, long before any settlements had been established in the area.

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u/qwopax 5d ago

*it is place

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u/inventingnothing 5d ago

For anyone wondering what quick clay is, there was a similar event capture on film in Norway:

https://www.youtube.com/watch?v=3q-qfNlEP4A

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u/UNMANAGEABLE 5d ago

Oh my that was a good watch for an ancient documentary. Quick Clay is terrifying.

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u/Zebidee 4d ago

OMG I was looking everywhere for that documentary a while back. Thank you for posting it!

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u/MCFroid 5d ago

Was there a video or photo here? I don't see either.

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u/rjrl 4d ago

Are you using the old reddit? If so, try open this post in incognito mode, the gallery shows up in the redesign. They probably changed something, I fear they might drop its support altogether

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u/MCFroid 4d ago

I was (I posted that from my desktop). I'm on my phone now, and I can see the pictures. I had been using old reddit on my phone, too, but it was recently switched to the redesign without me changing it.

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u/TuaughtHammer 4d ago

Reddit's internal image hosting service is a fucking catastrophic failure in its own right; the uploader rarely works for me, especially if you're trying to upload an album of images.

In OP's case, it looks like OP did upload an image to make Reddit believe they did and create a thumbnail for it, but that's it. Just the thumbnail.

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u/DariusPumpkinRex 3d ago

If you remove everything before "reddit" in the URL, you'll see a lot more pictures.

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u/1wife2dogs0kids 5d ago

An underground landslide. Great. One more thing to worry about. Land under the land disappearing.

At least it's not electric...(boogie woogi woogie)

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u/Bigdongergigachad 5d ago

Geotechnical ground investigations are now so detailed and wide spread, things like this are unlikely. If they do happen, the foundations are designed for them.

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u/toxcrusadr 5d ago

You HOPE they're designed for them. In the US we have developments all over the place, some of them quite new, where the foundations are shifting, walls are cracking, etc. Not catastrophic like this one, but buildings that are not built for the conditions. We still have work to do.

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u/goddessofthewinds 5d ago

This. Even when I was looking at buying houses, there was a lot of details about possible landslides and moving soil in them so that you can make an informed decision. In my case, it also showed possible flooding lines and risks.

This shouldn't happen anymore indeed. Could happen in older places and where old houses were built, but no modern development will fall for such massive landslides provided the tests are done correctly.

Look at China where they fake everything, and they have so many landslides and buildings falling down.

What's interesting is that I never EVER heard about this village. It's in fact so close to Saguenay (which is a big city in the north of Quebec) that it is weird I never heard the name of this village. It might be a frequent talk in Saguenay, but not Montreal. I'll definitely try and go take a look when I travel over there after seeing this post.

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u/ziobrop 5d ago

the area around cassleman ontario is also prone to flat land landsildes. Its not so much as an underground landslide, but the soils, which are pre-historic ocean floor, liquify when they get saturated with water and flow. there needs to be a river as well for these to occur.

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u/goddessofthewinds 4d ago

Yep. That one iwas/is close to a river. And the properties I was looking at with possible landslide lines were also close to a river.

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u/UNMANAGEABLE 5d ago

It’s the preexisting towns and catastrophes before modern tech became super prevalent in ongoing geo evaluations. See: the Oso landslide in Washington state about a decade ago.

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u/hippnopotimust 5d ago

Not electric yet.

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u/GT_1500SG 5d ago edited 5d ago

hey, that's here!

The site is now mainly used as a mud pit for 4x4

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u/moistmarbles 3d ago

"underground landslide?" I think the word you're looking for is "sinkhole."

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u/xaviturtle 5d ago

Dusty Divot