I've been down there several times, but never during a rain event/flood. However, as I hiked down the trail to Supai, it seemed that, for most of the trail, there were pretty good options of getting to reasonably high ground in the event of a flash flood. Down below Supai and at the campground in particular seemed to be the most sketchy areas in that regard. I'm not advocating for taking chances in hiking down to Supai when there's a risk of flooding, but am curious whether others have had trouble getting to high ground when there is flooding between the Hilltop and the convergence of Hualapai and Cataract Canyons (i.e. where you first meet up with Havasu Creek a mile or two before the village).