Guide / Skills
SkillsHow to read a canyon grade
The v/a/Roman-numeral system explained — what each axis means and how to use it to pick a route that fits you.
Photo: kallerna · CC BY-SA 4.0, Wikimedia Commons
Guide / Skills
SkillsThe v/a/Roman-numeral system explained — what each axis means and how to use it to pick a route that fits you.
Photo: kallerna · CC BY-SA 4.0, Wikimedia Commons
Open any canyon topo and you will meet a code like "v4 a3 III". It looks cryptic, but it is one of the most useful tools in the sport: a compact summary of what a descent will demand of you. Learning to read it turns a list of names into a map of difficulty.
The widely used European system rates a canyon on three independent scales. The point is that they are independent: a canyon can be very vertical but barely wet, or nearly flat but deeply committing.
Rated v1 to v7, this describes the technical difficulty of the descents: the height and awkwardness of rappels, the exposure, the rigging problems. A v2 has trivial down-climbs; a v6 has overhanging, free-hanging abseils that demand flawless technique.
Also rated 1 to 7, this captures how much the water itself is an obstacle: the force of the current, the difficulty of swims, the presence of hydraulics and siphons. A high 'a' rating means the water is actively trying to push you somewhere you do not want to go.
From I to VI, this rates the overall seriousness: the length, the remoteness, how hard it is to escape once you have started. A grade VI canyon may not be the hardest move-for-move, but it is long, far from help and unforgiving of error.
Match the grade to the weakest relevant skill in your group, not the strongest. If your rope work is solid but nobody is a confident swimmer, an aquatic 'a4' is the wrong choice however comfortable the rappels look. Build up one axis at a time, and treat the commitment numeral as the master variable: it decides how much margin for error you actually have.