EXTREMO SUR | INTERNATIONAL SCALE for RIVER CLASSIFICAtioN

Rivers are classified according to their level of difficulty, from I to VI: I is easy, VI is extreme and V is the limit of reasonable rafting.A plus sign "+" after the classification indicates that there are one or more rapids with a higher difficulty to the level stated, while a "P" after the classification indicates there is a portage. The level of difficulty of a river may vary significantly with the fluctuations in water levels.

Class 1. Easy.
Moving water, with small waves, clear passages, almost no obstructions.

Class 2. Novice.
Rapids with wide, clear channels which are evident without scouting. Occasional maneuvering may be required, but waves, rocks and other obstacles are easily missed.

Class 3. Intermediate.
Rapids with high, irregular and constant waves, which can swamp an open canoe. Tight passages which often require complex maneuvers in fast current and good boat control. May require scouting. Self-rescue is usually easy but group assistance may be required in long rapids.

Class 4. Advanced.
Intense, powerful, but predictable rapids requiring precise boat handling in turbulent water. Depending on the character of the river, it may feature large waves and holes or constricted passages demanding fast maneuvers under pressure. Rapids may require “must” moves above dangerous hazards. Scouting may be necessary the first time down. In case of accident, rescue is difficult and must be done by trained people. A strong Eskimo roll is highly recommended.

Class 5. Expert.
Long, very violent rapids, steep, congested chutes. They may contain large waves and unavoidable holes. They require a high level of fitness. What eddies exist may be small, turbulent, or difficult to reach. At the high end of the scale, several of these factors may be combined. Scouting is recommended but is not always possible. Swimming is dangerous, and rescue is difficult even for experts. A very reliable Eskimo roll, proper equipment, extensive experience and practiced rescue skills are essential for survival.

Class 6. Extreme.
These runs often exemplify the extremes of difficulty. They are unpredictable and very dangerous. The consequences of errors can be very severe and rescue may be impossible. For teams of experts only, after close personal inspection and taking all precautions.

PORTAGE
Boats must be carried over land to avoid an unrunnable section of the river.

WATER LEVELS
Depending on the meltdown and the time of the year, the river flow may be high, medium or low. When the level is high, the river flows faster; there are large waves and holes. With low levels, instead, the river changes its aspect: it gets more technical, new rocks, obstacles and holes appear.

The flow of the rivers reaches its highest level in spring, with the meltdown. The minimum flow is recorded at the beginning of the fall, and throughout this season, heavy rains cause rivers to increase their volume, sometimes reaching exceptional levels. During winter, snowfall and low temperatures accumulate water in the mountains, which will melt again with the first warm days in spring.
Fun does not depend on the water level. With Extremo Sur it is always guaranteed!