Climbs of Colorado's Fourteeners can be classified as "walkable" or requiring a scramble (the use of hands and knees). Many climbs
require more nuanced classification, however, and that's where the Yosemite Decimal System comes in handy. You'll often come across the
classes of the YDS in the trail descriptions of individual peak pages.
The Yosemite Decimal System is a system for the difficulty of walks, hikes, and climbs used for mountaineering in the US. It was initially
created by the Sierra Club in the 1930s for use in the Sierra Nevada, and has been a standard ever since.
The five classes are as follows, in order of increasing difficulty:
Class 1: Hiking
Class 2: Simple scrambling, with possible occasional use of the hands
Class 3: Scrambling, a rope might be handy but is usually not required
Class 4: Simple climbing, with exposure. A rope is often used. Natural
protection can be easily found. Falls may well be fatal.
Class 5: Technical free climbing. Climbing involves rope, belaying, and other protection hardware for safety.
In addition, in the 1950s Class 5 was further broken down into sub-classes 5.1 (easiest) through 5.14 (most difficult) to describe
rock climbing, which is generally avoided in this guide.
Source: wikipedia.org
