"We were camped right at the side of the river, just a few feet from the bank. I am a light sleeper and woke up around midnight to the feeling like I was sleeping on a water bed. I poked my head outside the tent and sure enough, the water had risen quickly while we slept, and was beginning to fill our tents.
I yelled out to the rest of my group to wake up and get out because it was flooding. We were one of the last campsites on the river before a 200-foot waterfall (Mooney Falls). We couldn't go upstream, but couldn't go down the waterfall either, so we all climbed up on the rock on the canyon wall and waited it out. Throughout the night we could hear other campers clamoring for safety, trees snapping and cracking, and we could feel the rumble of boulders being moved along the ground by the water and debris.
When dawn came and the sun began to light everything again, we could see broken trees, destroyed tents, up-ended picnic benches, etc, all collecting together in a huge wet debris field. The water eventually went back down, leaving all that debris behind. It blocked our way back upstream, so once it was safe, we climbed down the side of the waterfall and were rescued by helicopter several hours later in the afternoon.
There were around 200 plus total campers and as far as I know, no major injuries. But I remember hearing people scream for each other, climbing trees, even using a rope to climb from one tree across the river to another in order to help their friend in the darkness.
Totally harrowing. Bummer was my tent had my car keys, cell phone, and wallet inside when it got swept away. Getting home required my mother-in-law to come and bring our spare car keys to us, which was a whole ordeal in itself since she had no idea where to find us."