Climbing Guide: How to Use the Yosemite Decimal System

The Yosemite Decimal System (YDS) is a method for rating the difficulty of walking trails and sport climbing routes. The system is mainly used for mountaineering in North America and was initially developed by Southern California’s Sierra Club. It is a scale of one to five, with each trail above five involving a vertical climb that uses decimals to rate the difficulty of the climb.

The YDS can also be used as a rating system for indoor climbing gyms. This system is often used in tandem with a Roman numeral system to grade the length of a climb, and a lettered protection rating that accounts for the protection from potential danger on the hike.

The YDS works by classifying the type of walk or climb into a series of classes based on the difficulty level of its hardest move. The fifth classification of five and above encompasses an advanced swath of climbing grades that are subdivided by a series of decimal-point grades.

Here is an overview of the YDS classes and what they mean for hikers and climbers.

1. 1. Class one: The first class in the YDS refers to a beginner’s-level hike with a low risk of serious injury. It includes the relatively flat, simple terrain throughout the trail as well as some steeper alpine trails where you may need to occasionally balance on your hands.
2. 2. Class two: Class two trails in the YDS system mostly consist of steep inclines and light scrambling (walking up an incline using the hands for support) though these trails are still considered simple. Proper climbing attire like hiking boots is recommended for class two trails and in some instances, a rope might be necessary.
3. 3. Class three: The third class of the YDS refers to trails with steeper inclines than classes one and two. These trails require a good deal of scrambling and might require some simple climbing that would require a rope and handholds. Falls can be fatal at this level, and extra precautions should be taken to reduce the risk of injury.
4. 4. Class four: The fourth class usually requires the use of a security rope, and carries one of the highest risks of long falls which can be fatal. Climbs in this class are nearly vertical, but will still have a few handholds. The amount of scrambling is greatly increased, creating more of a hiking and climbing hybrid experience.
5. 5. Class five: The fifth class of the YDS is a larger class specifically dedicated to technical climbing ratings. The class is divided into a decimal ranking system between 5.1 and 5.15. Hikes between 5.1 and 5.4 are relatively simple climbs that are totally vertical with plenty of foot and handholds. Climbs between 5.5 and 5.6 are easy-to-moderate, with lots of footholds but a little more difficulty than the former class. Climbs of 5.7 to 5.9 are intermediate routes that are moderately strenuous and may have some overhangs. Expert climbers can try routes that are 5.10 to 5.14, which are strenuous routes that have small footholds and a good amount of overhanging terrain. 5.15 climbs are virtuoso-level expeditions that very few people have been able to complete.

An additional grading system is used in tandem with the YDS to help categorize the length and strenuousness of a climb. These Roman numeral grades range from one to seven. Here is an overview of the YDS grades.

1. 1. Grade I: This grade involves a few hours of climbing.
2. 2. Grade II: Grade II usually involves about half a day of climbing.
3. 3. Grade III: This grade denotes trails that involve half a day or more of roped climbing.
4. 4. Grade IV: Grade IV refers to routes that demand technical climbing of moderate difficulty lasting about a full day.
5. 5. Grade V: These kinds are long enough to require an overnight stay at a location or a hike that lasts an entire day.
   
6. 6. Grade VI: This grade involves two or more days of technical rock climbing, as is particularly strenuous. This grade should only be attempted by experienced climbers familiar with the level of difficulty.
7. 7. Grade VII: Grade VII involves big walls and difficult climbs that can take at least a week to complete.

Protection ratings may also be included in a climb’s grade, using a ranking system similar to the one used for American cinema, with G standing for good protection, and X standing for minimal-to-no protection.

The YDS grading of a given trail or climb will typically contain three elements: the class, the grade, and the protection level. For example, if you are on a trail that is 5.5 I G, it is an easy-to-moderate climb that is nearly vertical with many footholds and handholds. The “I” means that the trail is a few hours long, and the “G” accounts for “good” protection throughout.

The decimal system can provide insight into the climbing route and what type of equipment they’ll need, as well as how many hours or days the trip is likely to take. Consult the rating of your desired climbing area and make sure you are properly prepared with the right gear and safety equipment before attempting to set out on your adventure.

Climbing is a high-impact activity with an elevated risk of serious injury. Practice, proper guidance, and extensive safety precautions are essential when attempting a climbing pursuit. This article is for educational and informational purposes only, and is not a substitute for professional instruction or guidance.

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