IN THIS MODULE
01 TRY THESE BEFORE READING ON
03 WHAT CHANGES AS THE NUMBER GOES UP?
17 Canyon Rating System
There is no single official worldwide standard for canyoneering ratings. However, in North America, one of the most commonly used systems is based on the American Canyoneering Association (ACA) style of rating.
The rating gives you a quick way to describe four things: the technical class, the expected water, the approximate time commitment, and—when needed—an additional risk rating.
TRY THESE BEFORE READING ON
• The Subway: 3B III
• Keyhole: 3B I
• Pine Creek: 3B II
• Imlay (Full): an advanced 4B route; check the publisher’s time and seriousness grades.
Do those codes make any sense yet? If not, that’s alright. By the end of this module, they should.
Example format: Technical Class • Water • Time • Optional Risk
“A rating gives you a starting point. It does not replace the beta, current conditions, or your judgment.”
1st Column: Technical Class — 1, 2, 3, or 4
CLASS 1 & 2
• Class 1: Non-technical canyon hiking. Ropes are not required for normal travel; check the route details for specifics.
• Class 2: Basic canyoneering. Easy climbing/downclimbing may be involved, and a rope may help with handlines, packs, or assisting others.
CLASS 3 & 4
• Class 3: Intermediate canyoneering. Rope is required for rappels and technical climbing/downclimbing; basic problem-solving is expected.
• Class 4: Advanced-expert terrain may involve exposed climbing, difficult potholes, high stemming, multiple rappel stages, complex rigging, obscure anchors, or demanding problem-solving.
WHAT CHANGES AS THE NUMBER GOES UP?
The rating is telling you that the canyon is asking more of the team technically. That may mean harder movement, more complex rope work, more problem-solving, or more consequential obstacles.
2nd Column: Water Rating — A, B, or C
A — NORMALLY DRY
Normally dry or with shallow water; unusual conditions can change that. An A rating is not permission to omit checking recent conditions or the route description.
B — POOLS / SWIMMING
Standing water with no current or very light current may be expected. Pools, deep wading, and swimming can make water a significant part of route planning.
C — CURRENT / WATERFALL HAZARDS
Normally involves water with current and/or waterfalls. ACA may refine Class C as C1 through C4 as the current and water hazards increase. Specialized flowing-water techniques are not taught in this book.
3rd Column: Time / Duration (In Roman Numerals)
The time grade includes the approach, canyon, and exit. ACA uses optional grades I–VI. Treat them as broad estimates for an appropriately skilled group; beginners, large groups, changing conditions, and rescue problems can take much longer.
I, II & III
• I — Short: roughly 1–3 hours.
• II — Half-day: roughly 4–6 hours.
• III — Most of a day: roughly 7–12 hours.
IV & V
• IV — One long, full day: roughly 13–18 hours; start early, carry a headlamp, and consider a possible bivy.
• V — About a day and a half.
• VI — Two or more days.
4th Column: (Optional) Additional Risk — R, X, or XX
NO ADDED RATING
If no additional risk letter appears, the canyon still has the normal risks associated with its technical class, water, and conditions.
R — EXTRAORDINARY RISK
One or more extraordinary risk factors may complicate the descent. Solid technical skills and sound judgment are critical; ACA does not recommend R-rated canyons for beginners.
X — EXTREME
Multiple risk factors complicate the descent. Errors in technique or judgment are likely to result in serious injury or death; expert canyoneers only.
XX — DOUBLE EXTREME: Definitely life-threatening, even for expert canyoneers.
PUT IT TOGETHER
• 2B III = Class 2 technical difficulty + B water + a III time commitment.
• 3A I = Class 3 technical difficulty + normally dry A water + a short I time commitment.
• 3B IV R = Class 3 technical difficulty + B water + a long IV day + an added R risk.
“Know what every part of the rating means before you use it to decide whether a canyon fits your group.”
*CASE STUDY: A TETHER TRAP — SEVEN TEA CUPS, 2019
On July 26, 2019, a father and his 12-year-old son entered California's Seven Tea Cups in powerful flow. Although he had years of canyon experience, this was his first Class C canyon. Before swimming toward the next anchor, he clipped the end of a rope to his harness. Current swept him over a waterfall; the rope stopped him in the flow, where he struggled to breathe. His pack also trapped an arm. Both survived after a prolonged struggle, but his son was also swept over the drop.
Lesson learned: Rope attachment can create entrapment in moving water. Experience in dry canyons does not establish competence around hydraulics, waterfalls, or dangerous river crossings. If the flow, escape options, or required techniques exceed the team's training, turn back before commitment. A knife is emergency equipment; it does not make an improvised tether safe. Keep essential communication equipment accessible and distribute critical gear across the group.
Think it through: Which warning signs should have stopped this trip before the technical section?