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A day hiker in The Narrows of Zion National Park, Utah.

Camp > Guide > Backcountry Considerations > Rivers, Streams, and Flash Floods

Bubbling stream.Backcountry Considerations

Rivers, Streams, and Flash Floods

This page presents some basic information on the rivers, streams, and flash floods in canyon country.







All narrow canyons are potentially hazardous. Flash floods, cold water, and strong currents present real dangers that can be life-threatening. Your safety depends on your own good judgment, adequate preparation, and constant attention. By entering a narrow canyon, you are assuming a risk. It is your responsibility to know the current and predicted conditions. Your safety is your responsibility.

Flash Foods

Especially during the summer months and monsoon season, thunderstorms can move into canyon country very quickly and drop large amounts of rain. This rain concentrates with little warning in narrow canyons and washes and causes flash flooding. When the water is forced into these narrow areas, a wall of water forms that pushes along with great force anything in its path, including sand, dirt, rocks, boulders, shrubs, and trees. Water, along with the erosional agents it carries, has formed many tall, very narrow, and beautiful "slot" canyons that attract visitors from around the world. Slot canyons are a work in progress. Flash floods that created what you see today will alter these same canyons in the future.

Flash flood spilling over a pour-off in the Canyon Rims Recreation Area in Utah.When hiking, be observant. If you see rain, even 30 to 40 miles away, or if it is during or after a rain thunderstorm, avoid washes and canyon bottoms. If you believe that a flash flood may be approaching, immediately climb out of the canyon bottom and to high ground. Flash floods have been reported to sound like freight trains.

Flash floods can occur at any time of the year, but are typically most common in late Summer and early fall, corresponding to the brief, heavy thunderstorm activity normal for that time of the year. Flooding can occur under a clear sky as rainfall may drain from vast areas many miles upstream, funneling into washes, building volume, power, and speed. Flood water rushing down a canyon may sound like an approaching jet. It can appear as a headwall a few feet deep, becoming several feet deep within minutes, and reaching depths of up to 15 feet or more in a short time as it races toward the river. Without warning, flash floods can inundate deep, narrow canyons.

In 1997, flash floods in Antelope Canyon and in the Grand Canyon's Phantom Creek area killed a total of 13 people. Respect the forces of Nature. Flash floods can be strong enough to carry away vehicles. Flood waters typically recede in a few hours. Enjoy the thrill of experiencing this natural process from a safe distance.

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