Rafting is a recreational activity utilizing a raft to
navigate a river or other body of water.
Whitewater rafting can be a dangerous activity if the
proper precautions are not taken. Below is a generally
accepted classification system used to classify rivers
for rafting and boating difficulty:
Class I - Easy. Fast moving water with riffles and small
Class II – Novice. Straightforward rapids with wide,
Class III - Intermediate. Strong eddies and current, requiring
Class IV - Advanced. Powerful but predictable rapids requiring
precise boat handling in turbulent water.
Class V - Expert. Long, obstructed, or violent rapids
which expose paddlers to a high degree of danger, requiring
expertise and reliable equipment for safe passage.
Class VI - Unrunnable. Likelihood of death, or destruction
of equipment in attempting class 6 runs.
As expertise increases, and equipment becomes more durable,
or reliable, what was once considered class 6 becomes
class "5 plus", and eventually class five. The Grand Canyon
has swallowed whole expeditions, leaving only fragments
of boats, yet it is now run by commercial outfitters hundreds
of times each year, with relatively untrained passengers.
Whitewater is formed in a rapid, when a river's gradient
drops enough to form a bubbly, or aerated and unstable
current; the frothy water appears white. The term is also
used loosely to refer to less-turbulent but still agitated
Classification of whitewater
The most widely used grading system is the International
Grading System, where whitewater (either an individual
rapid, or the entire river) is classed in six categories
from class I (the easiest and safest) to class VI (the
most difficult and most dangerous). The grade reflects
both the technical difficulty and the danger associated
with a rapid, with grade I referring to flat or slow moving
water with few hazards, and grade VI referring to the
hardest rapids which are very dangerous even for expert
paddlers, and are rarely run. Grade-VI rapids are sometimes
downgraded to grade-V or V+ if they have been run successfully.
Harder rapids (for example a grade-V rapid on a mainly
grade-III river) are often portaged, a French term for
carrying. A portaged rapid is where the boater lands and
carries the boat around the hazard.
A rapid's grade is not fixed, since it may vary greatly
depending on the water depth and speed of flow. Although
some rapids may be easier at high flows because features
are covered or "washed-out," high water usually makes
rapids more difficult and dangerous. At flood stage, even
rapids which are usually easy can contain lethal and unpredictable