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Know Before You Go

Some Swift Water Considerations and Safety Concerns


Class C (swiftwater Canyons) require special considerations and training.  RopeWiKi has some excellent training info.  Please review these recommendations before venturing into Ouray Canyons.

Know before you go

Canyon Rating Systems

NOTE: Ratings refer to descents in normal conditions, during what is considered the normal season for the canyon. Adverse conditions, such as higher than normal water volume or colder temperatures, will increase the difficulty of the descent.




There are two standards for rating canyons: ACA and French. 


ACA Rating System

A standard ACA rating, such as 4B IV, consists of three pieces of information regarding the technical requirements, water challenges, and time commitment of the canyon. Some variations add additional information such as extraordinary risks and rock climbing rating. Many of these ratings are subjective and different authors may select different ratings. There's been much controversy on the ACA water rating classification.


French Rating

A standard French rating, such as v3a3 III, consists of three pieces of information regarding the technical requirements, aquatic challenges, and time commitment of the route. Many of these ratings are subjective and different authors may select different ratings.

  • Siphon: a constricted passage flooded with water that requires to hold the breath in order to traverse. Also called "sieve" or "sump".

  • Technical jump/toboggan: dangerous jump/toboggan with problematic start, trajectory and/or landing that may have disastrous consequences if not executed properly.


Press the RopeWiKi button below for a complete description of these rating systems.

Canyon rating systems

Safety Tips
extracted from Ouray Canyoning, Second Edition, Rev B
by Michael Dallin with Ira Lewis

Please practice these tips to increase the safety for you and your group:


In General

  • Acclimatize to the altitude for 2-3 days before attempting a route.

  • Drink plenty of water.

  • Use waterproof sunscreen and lip balm with sun protection.

  • Leave details of your route with someone and in your vehicle in case you are stranded.

  • Never attempt a route that is beyond the ability of you or any member of your group.

  • Never enter a canyon without adequate training from a reputable instructor.

  • Limit your group size to 6 or fewer in technical canyons. Delays caused by large groups can endanger everyone  in the canyon.

  • Never enter a canyon when storms threaten.

  • Start early to ensure that your route is complete before afternoon storms arrive.

  • If you are caught in a storm, beware of lightning. Stay away from points, summits and ridgelines that attract lightning.

  • Gauge the stream flow before entering the canyon, and during your descent. Abort your trip if the water is or turns chocolate or opaque colored, appears high or if rocks are flowing in the stream.

  • Wear a helmet.

  • Bring enough rope and webbing, with extra in case of emergencies. Most canyoners carry at least twice the length of rope needed for the tallest rappel in the route.

  • Ensure that your gear is not damaged or cut, particularly ropes.

  • Wear sufficient thermal protection (e.g., wetsuits or dry suits).

  • Be careful of slippery rocks. Twisted ankles can become major rescue ordeals.

  • If a flood threatens, seek high ground immediately and wait the flood out.

  • Be efficient in areas where there is no high ground to reduce your exposure in case a flood threatens.

  • Never enter or walk atop a snow tunnel that appears thin or unstable.

  • You must be self-sufficient. Rescues may take HOURS, if not DAYS to complete.


When Setting Up Rappels or Rappelling

  • Ensure that your anchor is safe. Have multiple group members double check the anchor.

  • Clip in to an anchor with a lanyard, cow’s tail or sling for protection from slips and falls. Unclip only after you are on rappel and have checked your setup.

  • Double check knots, rappel devices, carabiners and harnesses before beginning a rappel. Make sure the rope is threaded through your rappel device correctly. Check other members in your group.

  • Check that your rope reaches the bottom of the rappel – both ends if you are rappelling double-stranded.

  • Avoid running the rope through cracks or near snags that may cause rope pull problems.

  • Keep obstructions such as gear, hair and loose clothing away from your rappel device.

  • Keep the rope away from loose or sharp edges while rappelling. Reset the abrasion point between rappels.

  • Avoid swinging or bouncing on the rope while rappelling.

  • Do not try to avoid rappelling in water if doing so takes you out of the rappel fall line, even if you are scared of the pounding waterfall. Rope damage has occurred multiple times in Ouray canyons from rappellers doing this and slipping, which causes the rope to scrape across the abrasive rock as the rappeller pendulums back into the fall line.

  • When rappelling through water or into pools set the rope length so the rope ends at the pool’s surface. This reduces the risk of entanglement and drowning and keeps your rope from getting tangled in the stream flow.

  • Never use an autoblock, prusik, shunt or other backup device when rappelling through waterfalls or into pools. Never tie knots in the end of your rope in these situations. You can drown if you cannot disconnect from the rope quickly.

  • The first rappeller should check that the rope pulls smoothly from the bottom. Those at the anchor can fix any snags or rope pull problems before rappelling.

  • If your rope is stuck, try pulling it from different angles. Often this is enough to free the rope.

  • Check your rope after every rappel for sheath or core damage.


In The Water

  • Scout a pool for depth and hidden obstructions before jumping or sliding in.

  • Be cognizant of sieves and siphons. Getting caught could mean drowning within minutes. Sometimes they may be hidden underwater. They may appear at any time after floods, rockfall or logjams.

  • Don’t throw or drop a rope or other gear into the water. Most gear will sink and be difficult to find in flowing water.

Safety tips
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