http://www.youtube.com/watch?v=rhGgnr44SVI

From the description:

"Havasupai July 2012 flash flood. My Friends and I were hiking out of the havasupai falls area on saturday evening july 14th around 4:30pm when we witnessed 2 seperate flash floods. I got the second one on video. we were stranded on a hill side of this canyon for 4 hours until the waters died down enough for us to continue our hike out. This usually 3 hour hike took us 10 hours!"

In the video one of the people says, "It hasn't even been raining!"

Havasupai had a major flash flood back in 2008 that closed the area for almost a year. Some of the damage may never be recovered from, like the natural pools that were wiped out.

During that major flood there was no rain either, it was raining many miles away and all drained into the canyon.

Yikes! And that looked like such a nice place to pitch a tent too.

Floods of this nature are fairly common in the desert Southwest during the summer. We saw them fairly frequently in Canyon de Chelly; my Navajo crew members could identify the side drainage where the rain occurred from the color of the muddy water.

My most disastrous SAR incident was a flash flood of this nature which swept through a popular area (Tanque Verde Falls) one Sunday afternoon, killing seven people. We were a week in recovering the bodies.

It is a very bad idea to camp in close proximity to stream or dry gullies for this reason.

Thank You.
I am a transplant to the SW. Never was around at "monsoon" season but I heard a lot of stories. Like many things it is very helpful to actually see it.

Thanks again.

Nomad