You’re hiking up a dry riverbed. Your surroundings are fascinating, surreal. Walls of variegated sandstone rise steeply on both sides. Distant thunder upslope warns you of possible danger ahead, but too far ahead to worry about now. You scan the sky above. Nothing but blue with puffy clouds scudding overhead.
An ominous rumble from upstream begins to echo between the canyon walls and draws closer with frightening rapidity. The ground begins to shake. You search anxiously for a way out of the canyon. Seconds after you succeed at dragging yourself up a sloping crack in the wall, a freight train of water preceded by a wall of debris thunders down the once dry river bed and washes away your tracks.
Flash floods can appear out of nowhere without much-advanced warning. It does not need to be raining where you are. The phenomenon that produces the roiling water may be far up from your location.
To borrow from medical terminology, here are some risk factors for flash floods: southwestern deserts, narrow canyons, washes and low-lying areas. Other risk factors are possible rain storms or thunderstorms up the slope and spring thaws.
Before you hike into any place that exhibits one or more of the above risk factors, talk to someone at a ranger station to see what the weather patterns are and what the chances are of encountering a flash flood. Always be aware of the possibility of flash floods. When hiking in an area where there is such a danger, constantly look for escape routes.
Never underestimate the power and the danger of flash floods. They have the power to rip out trees, smash buildings and wash out bridges. They can rapidly rise to a height of 10 or 20 feet. And the amount of debris that they push before them and carry with them is staggering.
Flash floods are nothing to mess with. Be constantly alert. They are killers. If you sense any danger of a flash flood, head for higher ground immediately and fast.
Never camp in low-lying areas that might be prone to flash flooding.