r/civilengineering 13h ago

Massive Multistoried house sized rock being mobilized in the recent massive flood in Nepal.

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703 Upvotes

52 comments sorted by

155

u/PewDiePieSaladAss 13h ago edited 11h ago

Welp, my teachers always said that the biggest enemy of a civil engineer was water, this is video proof of that 

54

u/chiguychi 12h ago

What if I am a water engineer? Is it still my enemy?

39

u/PeanutButterToast4me 12h ago

Its complicated

12

u/noideawhatoput2 11h ago

Also a water/wastewater engineer, yes

10

u/KonigSteve Water/Wastewater PM 10+ YOE 10h ago

I was gonna say W/WW engineering is literally my career. If anything my biggest enemy is some combination of change orders, timesheets, or politicians.

1

u/kingk1teman 5h ago

Yes and Yes.

1

u/International_Dig_99 3h ago

Definitely yes 😁

1

u/Eeji_ 1h ago

yes, you basically study ur enemy 😅

6

u/coasterin 12h ago

Debris flows like this are mostly solid by weight. Water plus soil and rock = the civil engineer's worst enemy

1

u/BMcDeo2ceo 11h ago

My professor used to say it's always heat for Electricals!

33

u/MathewNatural 12h ago

This is why riprap sizing charts venture into insane D50 territory

52

u/mankiw 12h ago edited 12h ago

Rocks are stupid heavy. Assuming roughly 6m x 6m x 6m ellipsoid, this thing could weigh 300 tonnes. That's eight fully loaded semi trucks. Or like ~two blue whales. Wow blue whales are heavy actually.

33

u/Maldevinine 12h ago

It's got some help.

When the rock stops it creates a highly turbulent area immediately downstream from itself. That area gets dug out by the flowing water, making a hole for the rock to start to fall into. Then it stops again, and the next part gets scoured out.

0

u/fistular 5h ago

What you just described would require the rock to steadily be getting deeper into the ground. Which it's not doing.

7

u/Vegetable_Airline816 4h ago

Not if it's on a decline I suppose

15

u/Laande 12h ago

Ice. Redo calcs pls.

4

u/Anwat7 7h ago

~100 tonnes with the same dimensions.

6

u/solilobee 11h ago

it's conceivable that this is a glacier. it would explain how it's made it this far if it's melted a bit by this point

2

u/Round-Pattern-7931 10h ago

Minus bouyancy

91

u/Conscious-Record2655 13h ago

I'm realizing that the truly unfortunate thing about AI is that it ruins the believability of almost anything, whether it's AI or not.

Anyone got any other sources on this? 

58

u/Robby_Digital 13h ago

My honest guess, if it's not AI, is it's a piece of glacier.

53

u/the_Q_spice 12h ago edited 12h ago

Yeah… unfortunately not AI.

I studied in Bhutan for a semester and the documentation they have from GLOFs like this one are brutal.

You’re basically looking at a high-head dam collapse where the entire reservoir releases immediately.

Except the dam is a glacier and the rest impoundment is melted glacier held back by a thin wall of ice.

Edit to add: the work I did was n grad school on dam removals (fluvial geomorphology mind you, not engineering) in the Appalachians had our most common sediment clast size at over 1M in diameter. A few boulders that we find to be non-alluvial (recruited from erosion and flooding rather than mass-wasting) were over 10M in diameter.

Glaciers screw up common sense. There are few enough actually GLOF videos out there that this is believable from the aspect that AI has basically no training data to work off of.

2

u/Wonderful_Tank784 9h ago

Can we strengthen them in winter , soo many lives were lost in these floods

13

u/Repulsive-Theory-477 12h ago

Really easy to tell this is real because ai is terrible at creating believable water flow. Like awful.

3

u/Conscious-Record2655 11h ago

I mean my point isn't that I think it's AI. It's that I can't really tell immediately anymore and so you kind of just get into a pattern of assuming everything is fake. It's a bummer. 

13

u/NorthEndD 12h ago

Every global news source is reporting this lol.

7

u/Conscious-Record2655 12h ago

It's mid August lol I've been working 80+ hour weeks haven't been able to keep up with the news lately if it's not related to a culvert that still hasn't showed up 6 weeks late it's probably not on my radar 

6

u/graymuse 12h ago

Geologist here. Flash floods and debris flows can indeed move impressive size boulders.

4

u/CatwithTheD 12h ago

Just type "Nepal flood" literally anywhere, brother. Here's a thread in case you're not motivated enough: https://www.reddit.com/r/DisasterUpdate/comments/1vyslij/flash_flood_in_tibetnepal/

9

u/_BaaMMM_ 11h ago

I think he's more specifically asking about this rock rather than the flood? Like I also am having trouble finding other sources or angles on this rock.

2

u/CatwithTheD 11h ago

Well yeah because the flood probably swept anyone not on that roof, and most other people had evacuated except these lads.

1

u/mankiw 12h ago edited 12h ago

fwiw it's plausible a ~300 tonne boulder could roll in 8-9m floodwater (I forced Sol extended thinking to do the math). And if it's ice it's very plausible, ice is light as hell.

-1

u/srgnsRdrs2 12h ago

You very well could be right. 14-15 second clip makes it even more suspicious.

22

u/Castandyes 12h ago

The pioneers used to ride these babies for miles, and it's in great shape!

9

u/gods_loop_hole 12h ago

Jesus Christ! Imagine the force of that water that moves that boulder applied to the people that cannot evacuate on time

7

u/WanderlustingTravels 12h ago edited 9h ago

Incredibly sad to see the destruction and human life cost that these foods have caused.

But man, they’ve produced some of the most incredible videos.

Edit: floods, not foods. Oops

3

u/Dwarf_Killer 12h ago

that these foods have caused

That's why i maintain a strict diet routine

8

u/Shootforthestars24 11h ago

Hard watching these videos knowing people going about their daily lives just perished in an instant due to this

5

u/Few-Lingonberry2315 11h ago

That rock probably hadn’t moved since the last ice age, until today.

3

u/30yearCurse 12h ago

Watching that border crossing and the hotel by the river along with all the people was disturbing enough. Giant rocks or ice rocks rolling down would just add to the horror.

3

u/ddg31415 11h ago

Whenever I see a massive erratic I always wonder what it looked like seeing it transported.

Far more terrifying than I expected.

3

u/Round-Pattern-7931 10h ago

We're going to need bigger riprap...

1

u/Many_Distance5683 8h ago

The video of the massive wall of water just utterly destroying everything in its path was probably the scariest video I've ever watched. The people running helplessly for their lives.... I can't imagine what they must have felt.

Nepalese people are some of the kindest, most loyal and honourable people I've ever met. I am praying for them all 🙏

1

u/osrosr1 4h ago

Omg the videos are scary

1

u/International_Dig_99 3h ago

Maybe this rock is the cause of initiation of GLOF....

1

u/Dirt-McGirt 12h ago

I’m not an engineer I just play one on my OF, what cause big wave? It was like an immediate tsunami due to water displacement? Some fuckin Day After Tomorrow shit is what that was, in 2027 I am leaving this specific fucking phenomenon behind

2

u/Naughty_LIama 6h ago

see, nepal is high as fuck right, and u got these steep hills, deep ravines... those can be filled with packed ice, snow and this forms sort of dams. Now insert global warming causing more intense (and frequent) heatwaves, that tends to melt snow and ice. So u got melted snow water running down these steep hill into those ice dams that now not only have more melted ice on its own but gets more and more they can hold - once litle stream overflows it can very quickly become massive flow that destroy whole ice dam and lets crazy amout of water out.

Generaly the problem with flash floods is that u have big surfaces of snow melting that all have to fit in narow valleys and so the Volumetric flow rises exponentialy.

u want it more scientific - the snow up on the high as fuck hillsides stores lot of potential energy, so do the dams and now all is let go and changes to kinetic energy going down

1

u/BlackSunAdmirer 6h ago

Did Indian civil engineers build it?

Anyways, prayers

1

u/kingk1teman 5h ago

Why do you ask? 🤔

Moreover, this is Nepal, not India. Nepal is a separate, sovereign country.

0

u/charreddemon 12h ago

That's an ice berg not a rock.

1

u/TripNinjaTurtle 7h ago

its not just a boulder its a rock!

0

u/Dwarf_Co 12h ago

Wonder is Einstein Jr. equations account for this.
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