Maybe creeks are different where you're from, but as a young individual in the US northeast the idea of being "swept away never to be seen again" by a creek is a bit comical, torrential rain or not. You'd make it about a few yards before hitting one embankment or other and clamber out. Cold and wet, sure, but certainly to be seen again.
By the way, it is sunny overhead. The water is coming from a torrential downpour some miles away in the mountains. This is normal in New Mexico which experiences highly localized heavy downpours during July/August.
To point out the reason. In the northeast a small creek represents a small drainage area. In the Southwest a small dry creek can represent a large drainage. All the water dropped by a thunder storm will end up in it.
I remember one time flying over the southwest with the light just right and you could see vast drainages with thin thin cracks that are the actual channels cut down into the sand stone.
Indeed, in the South West, flash flooding carries families away occasionally. This year we've had exceptional fires, and the drainage from burn scars often carries what used to be a forest along with it. I don't know about GP's situation, obviously, but there is definitely a spectrum of intensity with regard to sudden water flows.
