Alright, so new changes to FLOWS! Basically what was happening was: Some HUGE basins showed up, and the program was exceeding my humble 8gb of RAM when trying to generate a diagnostic image (that also happened on cuts where there were thousands of basins). BUT after some tinkering, I discovered that I was doing some very heavy processes on image generation that were not necessary. So I adapted my code, and now a whole terrain cut of 160k square kilometers (about 39 million acres) can be processed without crashing!