About. Days?, Weeks? Months? Years?
It’s an amazing amount of water released very quickly, I’m just skeptical that it accumulated in as little as hours as some are claiming. I mean, maybe. Just seems to strain credulity.
Nepal Disaster Update: Where Did All the Water Come From + A Second Landslide? By Geology professor Shawn Willsey. It lasts about 25 minutes. His current working theory is the initial collapse fell ~4K feet into a second glacier and the debris fell another ~3K feet into the river below.
https://www.youtube.com/watch?v=ILngACgq4w8