River Classification
River Class illustrates how difficult a river is to navigate. It is determined by the hardest rapid
class on a given run. This scale helps give information about rafting or navigating a river in
a different vessel such a canoe or kayak. The international river class scale is summarised below:
Class I
Moving water. Few obstructions, all obvious & easily missed. Rapids require little to no manoeuvring. Risk to swimmers is slight; self-rescue is easy.
Class II
Easy rapids with obvious wide, clear channels, no scouting. Occasional manoeuvring required, but rocks & hazards are easily missed. River features can be big enough to soak a raft.
Class III
Technical Rapids with moderate, irregular waves; obstacles may be difficult to avoid, can require complex manoeuvres in fast current & good boat control in tight passages or around ledges. Large waves, holes or strainers can be present but are easily avoided.
Class IV
Intense, powerful but predictable rapids requiring precise boat handling in turbulent water. May be large, unavoidable waves & holes or constricted passages demanding fast manoeuvres under pressure. Rapids require must make moves above dangerous hazards. Scouting necessary first time.
Class V
Expert. Extremely long, obstructed, or very violent rapids which expose a rafters to added risk. Drops may contain large, unavoidable waves & holes or steep, congested chutes with complex, demanding routes. Rapids may continue for long distances between pools, demanding a high level of fitness. Swims are dangerous, and rescue is often difficult even for experts. Proper equipment, extensive experience, & practiced rescue skills are essential.
Class VI
Extreme and Exploratory. These runs have almost never been attempted and often exemplify the extremes of difficulty, unpredictability and danger. The consequences of errors are very severe and rescue may be impossible. For teams of experts only, at favorable water levels, after close personal inspection and taking all precautions.
Water Levels
Water levels in the mountains are affected mostly by the snow pack form the previous winter. A weak snow year can mean a low water year where a strong snow year can mean a high water year. The temperature in the spring and summer also affect the water levels. A consistent warming through the spring and summer mean that the water is released predictably. A sudden hot spell in the spring could cause too much water to be released at once creating conditions that are unsafe to raft in. A cold spring could delay the start to the season by trapping the water in the mountains.
With all the factors affecting water levels it is next to impossible to predict more than a few days in advance. There are times of the year when high water is more likely, as well as times of the year when low water is more likely. In the end it is up to Mother Nature to decide what will happen and when.
Both high and low water have advantages and disadvantages. High water can be very exciting with large rapids and a fast river flow. However some rapids will have to be portaged (walked around) during high water due to safety concerns. Low water allows us to challenge rapids considered too dangerous at higher water levels. We also get the opportunity to surf and play on rapids when the water is lower. Sometimes when the water is low some rapids will decrease a class level, you will always be informed of this and how it will affect your trip. The randomness of weather and water levels are part of what make rafting the great adventure that it is!
For more information on water levels give us a call @ 1 888 670 8853
