The winds. Most ocean waves are less than 3.5 m (12 feet) high. The stronger the wind and the greater the distance the wind blows over the water, the higher the waves. The highest wave ever recorded was measured in 1933 by an American tanker in the Pacific. It was 34m (112 feet) high, as tall as a nine-storey building. Immense waves are sometimes created when volcanoes erupt under the sea.

Almost all raindrops begin as snowflakes. They are formed in clouds that are at least partly high enough for the air temperature to remain below freezing. When snowflakes drift into a lower, warmer part of the cloud, the flakes melt and become raindrops.
Like snowflakes, raindrops are not all the same size. They usually range from about .02 inches (.05 cm) to .2 inches (.5 cm) in diameter. The largest raindrops are the ones found during heavy rainstorms, when people are likely to say it's raining cats and dogs. A raindrop size can change as wind tosses it around or as it collides with other raindrops.
Throughout the years 1898 to 1904, Wilson Bentley not only photographed snowflakes, but studied raindrop size as well. He filled several pans with at least 1 inch (2.54 cm) of fine, sifted flour, placed them outside during a storm, and found that each raindrop that landed in the flour-filled pan formed a doughy pellet. After the pellets dried, Bentley measured them-some were almost .25 inch (.64 cm) in diameter. Bentley studied the raindrops from 70 different storms and made 344 raindrop measurements.

One of the least known facts about raindrops is that they are not shaped like teardrops. Special wind experiments done in laboratories have made it possible to suspend, or stop, raindrops in midair. Scientists have found that raindrops are actually shaped like hamburger buns!
A heavy rainfall can change the landscape. In moist places, rain falls fairly regularly. Floods in these areas are likely to be widespread and tend to rise and fall slowly, because the soil and plants absorb the rain. Desert areas, however, often have wild, rough floods. Storms in desert areas tend to be heavy rains that last for a short time. Because the soil has been baked dry by the sun, it is difficult for rain to soak in quickly. Since there is little or no vegetation to help slow water runoff and hold soil in place, rain rushes across the land in dirt-filled, swift-moving sheets or streams. This kind of rapidly flowing, dangerous water is called a flash flood. Flash floods usually occur very quickly, almost without warning-
A heavy rainfall in an agricultural area may wash away good topsoil. The faster the water flows, the more topsoil it sweeps away. Topsoil is important because healthy crops depend on this nutrient-rich layer of dirt to grow. Fortunately, farmers can use certain patterns of plowing to slow down flowing water and to reduce the amount of topsoil carried away.

Freezing rain forms when raindrops are supercooled, that is cooled below the freezing point without turning into ice. Upon contact with a cold surface, freezing rain immediately turns from a liquid to a solid, covering everything under a layer of ice. Although the icy layer becomes a sparkling winter spectacle when the sun shines on it, ice-coated tree branches and electrical wires can be dangerous if they become too heavy and snap. Streets and sidewalks covered with a slippery coating of freezing rain are treacherous for traffic and pedestrians.