A couple of days later, I was fortunate to witness what she was talking about. If they flowed all the time, Zion's waterfalls would be world class. Many drop thousands of feet. But most are ephemeral, some lasting only minutes after the rain stops. Zion also is a place of occasional massive landslides, falling boulders and earthquakes.
Most fatalities here are hikers trapped in slot canyons during flash floods.
Other risks include lightning, mountain lions and hiking in this desert terrain without enough water. My first stop in Zion was Kolob Canyons, just off Interstate 15 at the north end of the park. I was glad I didn't miss the rugged finger canyons. When I climbed out of my rental car, I was greeted by absolute silence. I felt like an intruder and tried to walk softly.