Hiking canyons can be dangerous when storms hit – what you need to know to stay safe

Canyons are narrow valleys with steep walls that channel water like a funnel during storms. Even if rain falls far away, the water can rush downstream quickly because of the canyon’s steep slopes and narrow passages. In arid regions like Arizona, where the ground is dry and hard, rainwater cannot soak into the soil easily. Instead, it flows rapidly over the surface, creating sudden floods called flash floods. For example, in 2018, a single day of heavy rain in Israel’s Tzafit Canyon—equivalent to a year’s worth of rainfall—caused a deadly flood that killed 10 hikers. These floods can rise within minutes, trapping people who may not realize danger is approaching until it’s too late.

Monsoon season, which occurs in regions like Arizona during late summer, brings intense rainfall over short periods. In August 2026, powerful monsoon storms caused a flash flood in the Grand Canyon, killing at least two hikers and leaving another missing. Survivors described water rising rapidly over the trail, forcing them to cling to ledges. The storms were tracked using radar timelapse images, showing heavy rain moving over areas upstream of the canyon. Monsoon rains are unpredictable and can create life-threatening conditions even when the sky above the canyon appears clear.

The shape and composition of the land influence how floods develop. In arid environments like the Grand Canyon or Israel’s Negev Desert, dry soil forms a hardened crust that prevents water from absorbing into the ground. Without vegetation to slow the flow, water rushes down slopes faster, increasing flood intensity. The Grand Canyon’s steep walls drop 1,500 meters over less than 5 miles, creating a dramatic elevation change that accelerates water movement. This geology makes canyons particularly hazardous during storms, as water can rise unexpectedly and with great force.

Survivors of the 2026 Grand Canyon flood described the terrifying speed of the rising water. One person compared the sound of the flood to a freight train, a common warning sign of an approaching flash flood. The water rose so quickly that hikers had to scramble to higher ground or ledges to avoid being swept away. In another incident in 2018, hikers in Tzafit Canyon had only minutes to react before a wall of water engulfed them. These accounts highlight how sudden and violent flash floods can be, even in places where rain is not falling directly overhead.