The Different Classes of Rapids Explained

Rafting in Colorado comes in many different forms. From river floats to very technical and advanced rapids, there are opportunities for adventure seekers at ever level! It may seem intimidating to find the perfect trip for your group, but we are here to explain and demystify the rapids’ rating system.

Rafting trips are broken down into different classes, using the International Scale of River Difficulty (ISRD) rating system. These begin with Class I (less difficult) to Class VI (most difficult) and consider the elements of the river and the skill level needed to raft it. More specifically, the ISRD takes into account river flow (the rate at which the river runs), its gradient (changes in elevation), and any obstructions or constrictions in the river. Obstructions can refer to trees, rocks, or anything that blocks a river’s flow, and constrictions references the narrowing of channels leading to increased rapids.

Classes of Rapids

Class I: These rapids are the most gentle and fall into the “easy” category.

  • Small waves (at most 2 feet high)
  • Easily avoidable obstructions
  • Low risk
  • Also great for canoeing and wildlife viewing
  • Best for beginners

Class II: Easy rapids with slightly larger waves and disturbances

  • Clear channels that are obvious without scouting
  • Wave height up to 3 feet
  • Visible obstacles with some maneuvering required
  • Low risk
  • Best for beginners

Class III: Rapids with higher, irregular waves.

  • Narrow passages that often require precise maneuvering
  • Stronger currents
  • Often necessitate scouting
  • Waves can reach 3 feet high
  • Well-trained guide needed
  • Best for intermediate rafters

Class IV: Long, difficult rapids in turbulent water

  • Often require complex maneuvering
  • Constricted passages and obstacles
  • The course may be hard to determine and scouting is necessary
  • Higher risk of capsizing
  • For advanced paddlers only (typically age 12 and up)

Class V: Extremely difficult, long and very violent rapids

  • Upper limit for commercial rafting
  • Large drops with unpredictable rapids
  • Many obstacles
  • Scouting required
  • Experts only with experienced guides

Class VI: Very dangerous and un-runnable

  • A high possibility of serious injury or death
  • Violent and unpredictable
  • Scouting can be almost impossible

Arkansas Valley Adventures has 3 main outposts throughout Colorado with various sections of whitewater for everyone!

For a beginner rafter Class I – Class III trips will be the best option.

Kremmling, CO – Upper Colorado Scenic Float Trip (½ Day OR Full Day Adventure) Great for families! This trip is mainly going to be a scenic float, with a 20 to 30-minute section of Class II whitewater. On the Colorado River you will see gorgeous views of Gore Mountain Range, old minding homes, wildlife, and even a stop at Radium Hot Springs.

Idaho Springs, CO – Gold Rush (1/3 Day Adventure) Best for younger children and guests who have not been rafting before. Class II and Class III rapids will be splashy and a lot of fun for all ages!

Buena Vista, CO Browns Canyon (½ Day OR ¾ Day OR Full Day Adventure) With trip lengths ranging from 10 miles to 16 mile through Browns Canyon there is a day trip for everyone! Browns Canyon gives you the best of both worlds; fantastic views of Browns National Monument and thrilling Class III rapids.

For an intermediate rafter/ guests age 15+ we have Class III – Class IV trips available.

Idaho Springs, CO – Upper Clear Creek (½ Day Adventure) Best trip for intermediate rafters or beginners who are in good physical shape and looking for more adventure! Class IV rapids will have you paddling hard and getting soaked along the way.

Idaho Springs, CO – Outer Limits (¾ Day Adventure) Looking for a longer trip?! Outer Limits gets both Class III and Class IV rapids. With a delicious lunch from Smokin’ Yards BBQ riverside this trip is great for intermediate rafters looking for a day packed with fun!

Buena Vista, CONumbers (½ Day OR Full Day Adventure) The numbers section of the Arkansas River is jam packed with continuous Class IV rapids. Be ready to paddle hard, get splashed, and have a great time on the water!

For advanced rafters/ guests age 15+ we have Class IV- Class V trips available.

Idaho Springs, CO – Lower Canyon (½ Day Adventure) Class V rapids close to Denver. Guests are able to get high class whitewater and a fun, adventurous trip only an hour outside of Denver!

Idaho Springs, CO – Phoenix (Full Day Adventure) Looking for a full day packed with various class II – class V rapids? This trip takes you down all three sections of whitewater offered on Clear Creek. A great lunch from Smokin’ Yard BBQ is provided to keep you fueled up for the day.

Buena Vista CO – Pine Creek (½ Day or Full Day Adventure) The Pine Creek section of the Arkansas River is one of the most sought-after sections of white water for advanced rafters. Make sure to plan for mid-season trips due to the chance of high water from snow melt. This trip is the most advanced day trip offered. You will be paddling hard and maneuvering through some very technical sections.

Whitewater rafting with AVA allows for the entire family to get on the water no matter what their skill level is. Depending on the outpost there are some other activities that AVA offers. Such as zip lining, rock climbing, hiking, horseback riding, and UTV rentals. So, feel free to book online or discuss some great trip options with a sales associate at 877-723-8464.