Understanding Rock Climbing Difficulty Ratings & the Yosemite Decimal System (YDS)

When climbers discuss climbing roped climbing routes, the difficulty rating of the climb is often considered essential information. The difficulty rating gives a climber an indication of what moves, strength and/or skill the route might involve.

In North America, vertical travel is generally described using the Yosemite Decimal System (YDS). The YDS gives any describes any given hiking, scrambling, or climbing route with a Class. For Class 5 and Class 6 travel, it also includes a Rating.

Let’s start by discussing terrain classes.

Understanding Classes of Climbing Terrain

Terrain ratings describe the difficulty of traveling over the Earth. We describe difficulty in terms of:

• How easy it is to move forward?

• How serious are the consequences of a mistake?

First Class Terrain - The East Bluff Trail at Devil’s Lake State Park

First Class Terrain (Class I)

First class terrain requires no special tools or technical skills, beyond walking. Imagine a mostly flat, well-worn trail, that’s easy to negotiate.

First class trails can be paved, gravel, dirt, etc. It’s difficult to fall, and if you do, it’s tough to get very injured. The Grottos trail and the Tumbled Rocks trail are good examples of first class terrain at Devil’s Lake State Park.

Second Class Terrain (Class 2)

Increase the steepness, and you’ve got second class terrain. A hike up a steep trail, maybe using your hands here or there, would qualify. The consequences of a slip-and-fall event increase; it’s easier to sprain or break an ankle or wrist because when you fall, you fall further, and the terrain you fall onto is more irregular (i.e. sharp edges, slick surfaces, poor footing).

Many of the steep, popular hiking trails at Devil’s Lake, like the Balanced Rock, CCC or West Bluff trails, qualify as second class terrain.

Third Class Terrain

Third Class Terrain (Class 3)

Third class terrain pushes everything up another notch. Forward movement is more difficult; you have to think more about route-finding and you need better movement skills (balance, footwork, sequencing) to move securely. If you slip or fall, the risk of serious injury is higher.

Third class routes are rocky, and most people will use their hands regularly to help make progress and stay balanced. You may consider carrying a rope or taking other additional precautions, such as wearing a helmet. You regularly have opportunities to fall or slide short distances (5 - 15 feet).

Scrambling up or through the talus on the West Bluff, East Bluff, or South Bluff is a good example of third class movement.

Fourth Class Terrain (Class 4)

From reach fourth class terrain, take third class, add exposure (places where you can fall quite a ways), steepness, and make the terrain more challenging.

Since the main danger of fourth class terrain is the lack of security, some climbers will use a rope to protect against long falls. 

Fifth Class Terrain (Class 5)

Fifth class terrain typically means a vertical or nearly vertical cliff and significant exposure. Falling will almost certainly lead to serious injury and possibly death. Belaying is recommended, and climbers often use a helmet, harness, and rock climbing shoes to provide additional safety and assistance.

Sixth Class (Class 6) - Aid Climbing

Sixth class routes are, by definition, impossible to climb without using equipment to assist you. Aid routes require climbers to hang webbing ladders from hardware placed in cracks in the rock. The climber then climbs and stands on the ladder while placing the next piece of gear, to hang the next ladder from. This type of climbing is very technical, and much slower than “free” climbing.

the Yosemite Decimal System (YDS)

An additional system comes into play to more finely describe the difficulty of fifth class routes. In the United States, we use the Yosemite Decimal System (YDS). The scale starts at 5.0 (class + difficulty) and currently goes up to 5.15. When the scale reaches 5.10, a new wrinkle is added: we add a letter (a, b, c or d) to more finely indicate how difficult the climb is - 5.10a being less difficult than 5.10c, etc.

While route ratings can be helpful, it’s important to note they are subjective. The first climbers to successfully climb a route will offer a rating suggestion; over time, as many people climb the route, a popularly accepted rating will eventually settle out.

Ratings are also influenced by the history and culture of the area, which leads to routes of similar difficulties given different difficulty ratings in two different areas. Devil’s Lake, for example, is well-known for its “sandbag” ratings, meaning the routes are generally understood to be more difficult than rated.