Here's what science says (so far) about exactly what happens when sandstone gets wet—and what that means for climbing.
If you’ve ever been to Red Rocks, Indian Creek, or any other desert climbing area in the U.S., you’ve probably had the First Commandment of Sandstone drilled into your head: Don’t climb after it rains.
Why? Because sandstone gets weaker when it’s wet, and by climbing on it you risk breaking holds, thereby ruining routes and endangering yourself or others.
But that simple dictate—don’t climb after it rains—has spawned years of discussions about what “after” really means.