Managing Semi-Arid Watersheds: Watershed Basics - Safety in Arizona Watersheds

You may have heard news stories about people being swept away by flash floods. If you enjoy the outdoors and like to hike or ride in the canyons and arroyos of Arizona, the following is some information on how to be safe and stay alive.

First of all, it is important to understand what a watershed is and how it affects the movement of water on the landscape. When it rains in Arizona, it is usually during a storm event where there is a lot of rain in a short period of time. In this sort of even, the ground cannot absorb all the rain, so much of it runs off. Large canyons and small arroyos have all been created by fast moving water that is a result of several acres—even hundreds or thousands of acres—of land that shed water off of its slopes into the valleys creating streams and rivers of rushing water that disappear shortly after the rain stops.

The predominant storm season in Arizona is during the months of July and August. Morning skies may be sunny and blue, but large and powerful storms can appear very quickly in the early afternoon. When storm clouds are looming and rain is falling in the mountains, or uplands, water is moving downhill and quickly filling arroyos and canyons. People that are hiking or riding in these waterways don't sense the danger when the sun is shining where they are and the storm seems distant enough to be of no concern. This is when tragedy can strike. A wall of water can appear almost instantly, with no warning, and sweep away unsuspecting visitors. Several hikers have perished in recent years in narrow canyons.

The best advice is to closely monitor weather reports and heed all storm and flash flood warnings. Stay out of canyons and arroyos during the storm season if possible. However, if you do visit these areas during the storm season, make sure you conduct your activities in the early to mid morning hours. Always know where you are on the landscape and what is happening with the weather. If rain is on the horizon, move to higher ground.