Originally Posted by Infogypsy
But where in Utah ? I'm headed to Arches in a couple of weeks.
Don't worry. That video was taken at least 2 weeks ago. I know so because while in Las Vegas (July 22-23) I saw a short clip of that video on the local news. They showed the part where the guy's wife is running to get out of the wash, and the rolling mud scene right after that. It was something that had happened perhaps a day or two earlier.
But of course it can happen at any time. There can be cloudbursts over a mountain that fill the lower washes later on. Best to stay on high ground.
As for Arches, I don't know if they would have much of that. The nearest mountain is across the Colorado River to the south, so any such flows would be cut off at the river. I imagine the rangers would warn people if there were much danger in the park due to weather.