Slot canyons exist because of floods. A storm twenty miles away can send a wall of water down a canyon under a perfectly clear sky. That is why no one on our team enters a slot on a hunch.
The three checks
- The evening before: the National Weather Service flash-flood outlook for the whole drainage, not just the trailhead.
- At the trailhead: radar, cloud build-up upstream and any rain in the past 48 hours.
- Inside: debris lines, wet sand and the sound of the canyon. We turn around at the first doubt.
Monsoon season, from July to mid-September, is when we are strictest. Some days we swap the slot for a rim walk, and we tell guests why.
Rule of thumb
If the upstream sky is building, we are not going in. There is always another day.
A clear sky over your head tells you nothing about the canyon.
