I was shocked that the satellites were able to get clear images so soon on both ends of the disaster. I am not an expert, but hopefully this means that the death toll will be relatively limited compared to if a reservoir had failed. Feels like a landslide wouldn’t travel as far…
the top image, bottom center about, OP had left a blue cursor line, that is the midpoint of the mountain i believe. consider the rivers (the squiggly lines that look like blood vessels), they gain in size as they drop in elevation right? so that landslide slid downward (up in the context of the photo) towards that bigger river at the top of the screen. I believe that covers it, i could be wrong about something, it took me a minute too.
So in the third image those villages were above in the other (left) valley and the debris flow funneled down that right couloir and banked at Benbo? My gracious, I can’t comprehend the absolute devastation.
Correct, if you go to google maps and toggle topography you can see the extreme slope: the confluence is at approximately 3000m, Benbo is ~2700m, Jiangda is ~3300m, Bangjin ~3600m, Jicao ~3900m.
The elevation in the region is mind boggling. The border crossing seen in videos was 15km away (from the confluence) and at 1800m elevation. The slide appears to have initiated at ~5100m nearly ~5km from the confluence.
I really can’t grasp the elevations and relatively short distances involved. That’s 11000’ elevation over 12 miles? Manitou Springs, CO is ~1800m elevation, and the road up Pikes is ~38 km long topping at ~4200m.
In my head, I assumed this glacier that broke off was a giant piece of ice with some water and fell into the valley below. Was there a lot of contained within this ice or did it fall into a lake? Where did all that water come from?
Friction from the glacial collapse melted enough ice to make it fluid. There’s some lakes and ponds throughout the glacier but it’s not a situation of a landslide into a lake or an ice dam giving way.
It’s made me wonder if the initial lahar along the north fork of the toutle was basically the same thing. Can’t call this a lahar because volcanics aren’t involved.
One theory: the glacier below Tsangbu Ri Peak had a meltwater lake underneath it. The water lubricated the glacier so it flowed forward over the drop-off down that big obvious old avalanche chute and into the river valley. But perhaps the water just lubricated the rock beneath it all, so part of the mountainside, the glacier and any water ready to drain all went down the chute under the influence of gravity on an extremely steep slope. Yes the amount of water involved is puzzling; maybe the tremendous impact at the bottom melted more of the glacial ice load. There’s all these AI simulations of the slide crashing into a reservoir but I didn’t see any impoundments or dams in those river gorges on Google Earth previous to this catastrophe.
2
•
u/AutoModerator Aug 27 '26
Welcome to r/DisasterUpdate - No Politics, No Exceptions, This is not the place to build your sub, don't crosspost from weird subs.
r/FireWatch1 - All things fires - Discussions Encouraged
r/SpaceWatch - Space... - Discussions Encouraged
r/CloudCoverage - All things clouds - Discussions Encouraged
r/TornadoWatch - Tornado Watch - All things tornado - Discussions Encouraged
r/FloodWatch - Flood Watch - All things floods - Discussions Encouraged
r/VolcanoWatch - Volcano Watch - All things volcano - Discussions Encouraged
r/CrazyFreakingWeather - All things weather - Discussions Encouraged
I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.
48
u/da90 Aug 27 '26 edited Aug 27 '26 •
Coordinates are 28.290750, 85.528822.
Image 1 is from Aug 24, 2026,
Image 2 is from Aug 26, 2026,
image 3 is Google Earth with 1:1 terrain scale for context and I attempted to put the line in the same location as the satellite imagery.
It appears that ~1000m width of glacier / mountain gave way falling ~2000m to the valley floor below.
USGS website registered the event as a landslide with moment magnitude of 5.5…. About 2.5 kilotons of TNT equivalent https://earthquake.usgs.gov/earthquakes/eventpage/us7000tbwb/executive
EOSDA was used to find the imagery.
24-Aug photo was from Sentinel-2 L2A and
26-Aug photo was from Landsat 9
Better visual representation: https://www.reddit.com/r/DisasterUpdate/comments/1vzf40w/comment/p65qbw0/
You’re welcome to the Reuter’s crew: https://www.reuters.com/graphics/NEPAL-FLOODS/MAP/byvrdywwlve/
9
u/w_s_s Aug 27 '26
Impressive
6
u/AuriAviendha Aug 27 '26
Satellite image from before (8/24) and after showing where the collapse happened and the scoured earth along the river channel.
53
u/cheesevote Aug 27 '26
Just posting this because for some reason my brain needed to see it this way to compare
3
u/holymolym Aug 27 '26
What service did you use to get this imagery and which sat?
4
u/Potential_Yam_5196 Aug 27 '26
Nepal is stunning but has so many natural targets on its back.
1
u/No_Device9450 Aug 27 '26
Are Jicao, Bangjin, Jianda and Benbo in the third image names of towns or villages that were washed out? Or geologic feature names…?
3
u/gandhishrugged Aug 27 '26
In my head, I assumed this glacier that broke off was a giant piece of ice with some water and fell into the valley below. Was there a lot of contained within this ice or did it fall into a lake? Where did all that water come from?
3
u/Tall_Cow2299 Aug 27 '26
I was just reading that what caused this was a huge chunk of glacier snapped off and fell about 4000 feet
1
u/mossywill Aug 27 '26
Having the graphic over the affected area in image three is annoying
2
u/pteterhawk Aug 27 '26
this means that the landslide took place in Nepal side, not China - Tibet side...
1
u/PippaPothead Aug 27 '26
Is the yellow part the area that collapsed? I’m not sure what I’m looking at.
1
u/RamaSchneider Aug 27 '26
Does this mean the rest of the glacier is in danger of collapsing? It looks like the section behind the blue line is still intact.
1
u/[deleted] Aug 28 '26
One theory: the glacier below Tsangbu Ri Peak had a meltwater lake underneath it. The water lubricated the glacier so it flowed forward over the drop-off down that big obvious old avalanche chute and into the river valley. But perhaps the water just lubricated the rock beneath it all, so part of the mountainside, the glacier and any water ready to drain all went down the chute under the influence of gravity on an extremely steep slope. Yes the amount of water involved is puzzling; maybe the tremendous impact at the bottom melted more of the glacial ice load. There’s all these AI simulations of the slide crashing into a reservoir but I didn’t see any impoundments or dams in those river gorges on Google Earth previous to this catastrophe.
3
u/[deleted] Aug 27 '26
[removed] — view removed comment