For several decades, rock climbers have followed a difficulty scale designed by the Sierra Club known as the Yosemite Decimal Rating System. The scale ranges from Class 1 through Class 5, with Class 1 representing a simple walk along a defined pathway and Class 5 being defined as the first level necessitating technical rock climbing ability. Class 5 establishes a secondary rating system, with a 5.0-to-5.4 grade describing a steep section of rock featuring a number of solid holds.
A trail with a 5.5-to-5.7 rating should feature good holds as well, though the path will begin to increase in angle. No longer considered a steep ramp, any path rated 5.8 or better is a vertical climb. Finally, a 5.9-climb will feature some overhangs and considerably smaller holds, though an amateur climber can still handle themselves after a relatively short training period.
Beyond 5.10, the rating system further branches off to include grades like 5.13 b or 5.14 a. Anything above a 5.10 is considered very difficult and potentially dangerous for a casual climber. Paths rated 5.11 or higher should be attempted only by highly skilled athletes.