Like Ponderosa said, weather awareness. Those southern Utah canyons are deathtraps if you are not aware of the potentials. Some of those slot canyons drain tens of thousands of acres and when a large storm comes through, all that water is funneled through the canyons. In addition to the hiker death Ponderosa mentioned, another couple were stranded when their SUV dropped through the road where a bridge used to be. This happened both in the Paria canyon as well as the Virgin River narrows. These people were all lucky and survived. We hiked the Grand Gulch a few years ago. There were plenty of high places to camp but the very next week, some guy picked the wrong place to lay his head and died in his mummy bag, drowning in the mud and debris. Even on a sunny day, a thunderstorm 50 miles away can cause a flash flood where you are.