How To Survive: Flash Floods

The desert is really dry. Except, of course, when it's not. During canyon country's summer rainy season, storms sometimes blow up suddenly and drop buckets of rain on the hard-baked earth. All that water flows downhill, gathering in tributary canyons until a raging wall of water is ripping down the mainline. In that case, you don't want to be in its way. Tony Nester, survivalist and owner of Flagstaff-based Ancient Pathways outdoor survival school, tells you how to steer clear of flash floods:

Be aware of the critical times.
"Most flash floods, historically speaking, happen between July and September. That's our rainy season in the American Southwest. Most of the research out of the Grand Canyon—our "survival laboratory" here in the Southwest—indicates that 80 percent of flash floods happen between noon and 8pm. If it's during that timeframe, then you may have to alter your trip to avoid washes and slot canyons."

Know that you can't know.
"The difficulty with flash floods, and generally with desert storms in the Southwest, is they're very regional. Here in Flagstaff, when the rainy season starts in July, it can be raining, dropping hail and lightning, and they have blue skies just seven miles across town. So if you're hiking in a slot canyon, there may be blue skies above you, but 10 miles up canyon there could be a cloudburst. If that dumps all of its rain, it's coming towards you. You just can't predict the weather when you're in a canyon that's 1,000 feet deep and six feet wide."

Swimming won't cut it.
"The other problem with flash floods is that you're not only contending with water that may be eight or 15 feet high, but you're contending with silt and logs and debris. Some of the canyons out here haven't seen rain for 20 or 50 or 200 years, so you have all of this debris that's built up on the canyon floor, and it's headed your way."

Don't go in if you don't have to.
"We stay out of the slot canyons altogether during that time of year. If we have to go in canyon country at all, we go in the early morning hours, we still look at the clouds and weather, and then we have escape routes planned as we hike along. Study the maps, look at the lay of the land and, whatever you do, don't get caught in the narrows."

Don't try to "Ford" it.
"Most fatalities from flash floods happen in urban areas, not in the wilderness. It happens in Vegas, Phoenix, San Diego. People are always being plucked off of their SUVs by helicopter, because they decided to cross a flash flood area. It only takes two feet of swift-moving water to sweep a Ford F-150 off the pavement. There are hydraulics happening under the water that can just yank you away. We've seen Hummers, Jeeps and trucks get snatched up, and then you're in trouble. Bottom line: Don't try to cross a flooded wash. Wait it out for an hour, maybe two, maybe until morning."

Tony Nester has taught outdoor survival courses across the desert southwest and Rocky Mountains for 20-plus years through his Ancient Pathways school.