One of the witnesses said the water was as high as a tall coconut tree. And, reading that article, people drowned because the water was so strong, they had no control of where the water sent them. A fella who was in the water said people were washed away and he couldn’t do anything about it because he was trying to save himself.
So, it was a combination of drowning or getting killed by falling debris. I’ve looked at a lot of pictures of those scenes and bodies are in the streets under debris and you know those living people were hunkered down somewhere and not in the streets.
Think about all the debris that’s in that water, probably not much left of a good number of bodies.