Why you never camp in a dry wash …

I guess that's why you want a really good ground sheet.

–B.G.–

I'd definitely want a bathtub style floor on my tent there ;)

But as quick as it came, the water receded. Wow, it would be interesting to be there in person.

Watch this video of a flash debris flow. Pretty amazing. Long-video but worth the wait.

https://www.youtube.com/watch?v=SyOeZNSiyX8

@GGrey – They are powerful but I try to be elsewhere on vacation during the southwest "monsoons" season myself (usually right after the 4th of July). Many roadways can get flooded too.

Whoa…that'll get one's attention real quick. my wife and I love Joshua Tree, especially in the winter months.

I was hiking solo across Joshua Tree during a rainstorm at night. Visibility was 15' tops due to mist and clouds.

I heard a rumbling building somewhere in the distance, then rocks and boulders shifting. …couldn't even tell if I was on high ground or in a wash or how close the flood was. I ran in the first uphill direction I could find and heard the thing roar by below me in the darkness.

A first class night, one of the best I've ever had out there.

…

This is a long but sobering post.

My dad and I hiked across the Grand Canyon many years ago, and spent one night at the campground next to Phantom Ranch. Late in the afternoon a severe storm cell passed north of us, close enough to batter the CG with winds that knocked down a dead cottonwood tree next to our camp site.

About 10 minutes later the rangers came out and hustled us up to higher ground, overlooking Bright Angel Creek. Shortly after that, we stood in awe of a huge debris flow rumbling down the creek. I'd say it was about a city block long, and 2 or 3 times as wide as the creek had been flowing prior. Pushing the debris was a flow of water about the same width. None of this was very close to the level of the campground, and we were allowed to return to our site not too long after it started. However, the high, fast water continued well into the night, with large unseen boulders loudly cracking into one another like a giant marble game.

In the morning, the creek was down to normal level, but the creek bed was totally rearranged from the previous afternoon.

There were a few people slowly making their way downstream, looking for something in the creek bed. They told us some hikers had been up in a side canyon well upstream, and were apparently caught by a flash flood and washed into the creek. One of the searchers reached down and picked up something that looked like a pack strap. They said the hikers were probably down in the Colorado river. I never followed up to look for a story about it (this was pre-internet), but the search team told us that sort of thing happened occasionally; the hikers were up near a waterfall and probably never heard the flash flood coming.

A SAR type and a doctor paired up to summarize all the deaths in the Canyon dating back to the John Wesley Powell expedition (everyone who stayed with JWP survived, but some bugged out mid trip).

http://www.amazon.com/Over-Edge-Death-Grand-Canyon/dp/097009731X

They group the 550 deaths into flooding events, heat & exposure, and air travel fatalities (including the incident that spawned the current air-traffic-control system). Or post a date and I'll see if I can find the book around here and check for that incident.

I'm been in the Canyon during a monsoon rain and it is truly impressive how much the geology moves around in a short time.

Reminds me of the time early in my camping career I placed my tent inches from the high bank of a stream, and fell asleep before the heavy rain.

The low sandy bank was 3 feet down. WAS.

I unzipped my tent and stuck my hand in the river a few inches from my tent, now several feet deeper. Had it broke the bank I would have been Class IV rafting inside a tent.

I have always thought it was interesting and ironic that the two main forces shaping all the amazing typography in the Colorado plateau are flowing water and ice cracking rocks. That, and a lot of time of course. Hiking in some of those canyon it is sometimes hard to imagine either ever being important – until you have experienced something like that.

There is a pretty cool physics book I took a look at once that studied the hydrodynamics that created different types of formations in slot canyons, and how to read their history from that.

Flash floods are wonderful. I have seen a couple "100 year floods" that wiped out major portions of mature palm groves. Kind of sad for the short term enjoyment, but nature recovers.

Edit: I often sleep in washes. Nice soft sand.