Waterfalls often form in the upper stages of a river where it flows over different bands of rock. It erodes soft rock more quickly than hard rock and this may lead to the creation of a waterfall.
Sometimes, the land formation causes a waterfall. If there is a cliff or ledge naturally, rushing river waters will simply fall over the edge.
Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf.
Waterfalls can have a wide range of widths and depths, and this diversity is part of what makes them such a charismatic and interesting natural phenomenon.
Waterfalls are classified into 10 different types depending on the way they descend:
• Plunge: Water descends vertically, losing contact with the bedrock surface.
• Horsetail: Descending water maintains some contact with bedrock.
• Cataract: A large, powerful waterfall.
• Multi-step: A series of waterfalls one after another of roughly the same size each with its own sunken plunge pool.
• Block: Water descends from a relatively wide stream or river.
• Cascade: Water descends a series of rock steps.
• Segmented: Distinctly separate flows of water form as it descends.
• Tiered: Water drops in a series of distinct steps or falls.
• Punchbowl: Water descends in a constricted form and then spreads out in a wider pool.
• Fan: Water spreads horizontally as it descends while remaining in contact with bedrock
Angel Falls in Venezuela is the world’s highest uninterrupted waterfall, with a height of 979 meters (3,212 ft) and a plunge of 807 meters (2,648 ft). It is so high that at warmer times of the year, the water turns into mist before it reaches the stream below.
Victoria Falls is a waterfall in southern Africa on the Zambezi River at the border between Zambia and Zimbabwe. While it is neither the highest nor the widest waterfall in the world, Victoria Falls is classified as the largest, based on its combined width of 1,708 meters (5,604 ft) and height of 108 meters (354 ft), resulting in the world’s largest sheet of falling water. It has been described by CNN as one of the Seven Natural Wonders of the world.
Niagara Falls is the collective name for three waterfalls that straddle the international border between Canada and the United States; more specifically, between the province of Ontario and the state of New York. Niagara Falls is famed both for its beauty and as a valuable source of hydroelectric power. Balancing recreational, commercial, and industrial uses has been a challenge for the stewards of the falls since the 19th century. Niagara Falls is the most visited waterfall in the world. It is estimated that around 30 million people visit Niagara Falls each year, with numbers rising all the time.
Iguazu Falls is an extensive series of waterfalls along a 2.7-kilometers (1.7-mile) stretch of escarpment on the Argentina–Brazil border. The waterfall system consists of 275 falls along the Iguazu River. The majority of the falls are about 64 meters (210 ft) in height. Declared a World Heritage site by UNESCO in 1984, Iguazu Falls is often revered as the world’s most spectacular waterfall.
The Cascata delle Marmore (Marmore’s Falls) is a man-made waterfall created by the ancient Romans. Its total height is 165 meters (541 feet), making it the tallest man-made waterfall in the world. Of its 3 sections, the top one is the tallest, at 83 meters (272 feet). It is located 7.7 km from Terni, a provincial capital of the Italian region of Umbria.
Yosemite Falls in California is the tallest waterfall in the United States. It is located in Yosemite National Park and has a vertical drop of 739 meters (2425 feet). Yosemite Falls is actually made up of three separate falls: Upper Yosemite Fall at 440 meters (1,430 feet), middle cascades at 206 meters (675 feet), and Lower Yosemite Fall at 98 meters (320 feet).
Kaieteur Falls is located on the Potaro River in the center of Guyana’s rainforest. It is the world’s largest single drop waterfall by the volume of water flowing over it. While many falls have greater height, few have the combination of height and water volume, and Kaieteur is among the most powerful waterfalls in the world with an average flow rate of 663 cubic meters per second (23,400 cubic feet per second).
Horsetail Falls is located in Yosemite National Park in California. It falls off of the east side of El Capitan – the largest exposed granite monolith in the world. Around the second week of February, the setting sun hits Horsetail Fall at just the right angle to illuminate the upper reaches of the waterfall. And when conditions are perfect, Horsetail Fall glows orange and red at sunset. This natural phenomenon is often referred to as the “Firefall“, one of nature’s rarest phenomena.
Ban Gioc – Detian Falls is situated on the border between China and Vietnam. It is, in fact, the fourth largest cross-border falls in the world after Niagara, Victoria and Iguazu. The waterfall drops 30 meters (98 feet). It is separated into three falls by rocks and trees, and the thundering effect of the water hitting the cliffs can be heard from afar.
Gullfoss is one of the most popular tourist attractions in Iceland. The total cumulative height of the waterfall is 32 meters (105 feet) – this is actually split into two waterfalls. The upper waterfall has a drop of 11 meters (36 feet), while the lower waterfall has a drop of 21 meters (69 feet).
Many waterfalls around the world are used to generate hydroelectric power.
Some waterfalls freeze. It happens like this: the water in the river/stream that supplies water to the waterfall supercools (when water experiences a temperature less than its freezing point without becoming a solid) when the temperature dips below the freezing point (around -6 degrees Celsius). This results in a gradual slowing down of the flow as water molecules begin to stick to each other and form tiny, solid particles of ‘frazil ice’. Frazil ice, which has an oily appearance when seen on the surface of water, is a cluster of loose, randomly-oriented ice crystals shaped like tiny needles. It usually forms in rivers, lakes, oceans, and other water bodies containing turbulent, open and supercooled water.
Because waterfalls are so dramatic and dangerous, thrill-seekers like to perform stunts or events on or around them. People cross waterfalls on tightropes, in canoes, and even in barrels, which provide more protection. Many of these stunts, such as jet-skiing over Niagara Falls, do not go off as planned, and many daredevils have plunged to their deaths. Only two people are known to have survived a plunge from Niagara Falls without any protection. Those two men sustained serious injuries.