Classes of hiking – The Yosemite Decimal System

If you listen to the silly little podcast I co-host, you’ll often hear us talking about what class a hike or  scramble may be. Especially when we discuss routes versus a trail with such routes as the Wind River Range or the High Sierra.  (The future of thru-hiking!).

However, if you are mainly an on-trail hiker, the concept of different classes of hiking is not intuitive.

So what do all these “Class 1” vs “Class 3” vs “Class 4” designations mean?

Here’s a rough guide to the different classes.  These classes are based on the Yosemite Decimal System. (YDS) Other countries and/or activities will have different designations.

Though usually applied to climbing, the YDS covers hiking and scrambling as well. If you go off-trail, it is good to know the differences in the YDS classes.

Class I

On trail-hiking or gentle terrain. Hiking. Walking. Sauntering. You can mosey along without too much thought. Does not necessarily have to be on trail. Tundra walks would be a classic example of Class I hiking when off-trail.

  An alpine trail in Colorado
Off-trail on the tundra of the Kenosha range

Class II

Scrambling.  Usually but not always, off-trail.  Once in a great while you may need to use hands for stability.. But typically it means a person has to think a little more where the legs are being placed versus Class I hiking above. A talus field is a classic example of Class II hiking.

On Eldorado Mountain. PCO Mike DiLorenzo.

Class III

Typically off-trail hiking where hands and feet are both needed. A person will typically want to stash their hiking poles at this point.  Out croppings and such to place feet and hands are easily found. Can be physically strenuous but typically is safe as a long fall is unlikely. A “scrambly” ridge walk would be a typical example of Class III hiking.

Along a ridge in northern Colorado

Class IV

Essentially the same as above, but with exposure. Meaning, if you fall you will get very injured. Hand and footholds still easily found typically. Technical climbing equipment not necessarily needed. I, personally, will not do sustained Class IV hiking/climbing solo. But that is me. Many alpine climbing routes feature Class IV hiking/climbing.

Finishing a Class IV section of a technical route on Longs Peak


Class V

The start of true climbing for most. Rated 5.x and in various more difficult grades up to 5.15 (and those upper grades can often be sub-divided into ab, c, and d  Ropes, helmets, harnesses and other equipment typically needed. A 5.0 climb is not very different from Class IV above.  A 5.10 or above climb is only something that is typically done by very experienced people.  Some people will climb without any equipment for 5.x climbs but that is the exception rather than the rule esp. as the grades become more difficult.  At best, I’m a 5.8 climber with 5.6 being my comfort zone. So, I’ll let other people explain the fine details better. A nice chart by Mountain Madness explaining the intricacies of Class 5 climbing may be found at this link.

On Boulder’s Third Flatiron

Note: These classes are guidelines and not absolutes. You’ll often hear a person say “That’s an easy Class 4 climb.”   or “That’s a hard class two+ scramble” or similar. There is much gray area between the YDS classes. What is easy for one person may be difficult for another.  Also, I tend to think of “scrambling” as not needing technical equipment and “climbing” as needing technical equipment. For me, that is around Class IV or so.  Again, guidelines vs absolutes. 

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