Rain and also snow are vital elements in the Earth"s water cycle, which is crucial to every life ~ above Earth. Rainfall is the main means that the water in the skies comes down to Earth, whereby it filling our lakes and rivers, recharges the secret aquifers, and provides drinks to plants and also animals.

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A localized hefty summer rainstorm in Colorado

Here is a standard summer rainstorm; they are often small but intense. Other rain events are more "frontal" in nature, with huge nimbostratus varieties of clouds happen precipitation end a big area. 

Credit: Howard Perlman, dearteassociazione.org

Fortunately for everyone, water is a renewable source that move in a cycle through neither beginning nor end (but, you can put in her vote regarding where you think the begins). Water vapor (evaporated from oceans, lakes, forests, fields, animals, and plants) condenses and returns to earth as precipitation, when again replenishing reservoirs, lakes, rivers, underground aquifers, and also other sources of water and providing the moisture required by plants and animals... An unlimited water cycle.

The amount of precipitation the falls approximately the civilization may variety from much less than 0.1 customs per year in some deserts to much more than 900 inches per year in the tropics. Among the driest spots on planet is Iquique, Chile, where no rain dropped for 14 years. The world"s wettest spot, Mawsynram, in Northeastern India, skilled a typical of 494 inch of rain a year during the years 1989-2010, replacing the vault placeholder, Cherrapunji, likewise in Northeastern India, whereby a mean of 471 inches fell during the exact same period.

In case you"re wondering, the wettest place in the joined States, as displayed by data collected by the Western regional Climate Center, is on Mt. Waialeale, Hawaii, wherein an median of 373 customs of rain has actually fallen annually between the year 1949 and also 2008. Mt. Waialeale also experienced more than 642 customs of rain native July 1947 come July 1948! If friend think that"s something, Cherrapunji holds the single year record of 905 inch measured in 1861!

By contrast, the conterminous (the 48 "lower" states) United claims receives enough precipitation during an mean year come cover the says to a depth of about 30 inches. This is indistinguishable to about 1,430 cubic miles of water every year. What happens to the water after the reaches the ground depends upon plenty of factors such as the price of rainfall, topography, floor condition, density of vegetation, temperature, and the extent of urbanization.


Wide spread flooding in Lithia Springs, Georgia simply west of downtown Atlanta, after epos rainfall, 22 Sept. 2009. Impervious surfaces and also urban buildup causes rainfall to runoff much quicker, and with greater flooding consequences, throughout heavy rains.

Credit: NASA

For example, the straight runoff in a extremely urbanized area is relatively great, no only since of the density of roofs and impermeable pavements permits much less rain to infiltrate the ground, but additionally because storm-sewer systems carry more water directly to the streams and also lakes. In a an ext natural or undeveloped area, the direct runoff would certainly be substantially less.

In the united States, an typical of part 70 percent that the annual precipitation returns to the environment by evaporation from land and also water surfaces and by transpiration native vegetation. The staying 30 percent ultimately reaches a stream, lake, or ocean, partially by overland runoff during and immediately after ~ rain, and also partly by a much slower path by moving though the ground.

Much of the rain the enters the ground filter down right into subsurface water-bearing rocks (aquifers) and also eventually reaches lakes, streams, and also rivers wherein these surface-water body intercept the aquifers. The part of the precipitation that reaches the streams produce an average yearly streamflow in the United claims of about 1,200 billion gallons a day. By comparison, the Nations"s homes, farms, and also factories withdraw and also use around 355 exchange rate gallons a job (2010).


Amount the water received as soon as an customs of rain occurs

Have you ever wondered exactly how much water falls onto her yard during a rainstorm? making use of a 1-inch rainstorm together an example, the table below gives example of how much water falls throughout a storm for miscellaneous land areas.


AreaArea (square miles)Area (square kilometers)Amount of water (gallons)Amount the water (liters)
A roof (40 x 70 feet)0.00010.0002571,7436,601
1 acre (1 square mile = 640 acres)0.001560.00427,154102,789
1 square mile12.617,380,00065,780,000
Atlanta, Georgia132.4342.92,293,000,0008,680,000,000
United States3,537,4389,161,92261,474,000,000,000232,700,000,000,000


Consider because that a moment just how much rainwater part cities may receive throughout a year. For example, Atlanta, Ga. Averages around 45 customs of precipitation per year; multiplying this by the 2.293 exchange rate gallons displayed in the table as the number of gallons in 1 customs reveals that part 103.2 exchange rate gallons the water loss on Atlanta in an mean year. In a city the size of Atlanta, the every capita water usage is about 110 gallons every day or 40,150 gallons per year. Thus, the water indigenous a year"s precipitation, if it could be gathered and save on computer without any kind of loss, would certainly supply the requirements of about 2,574,000 people.




Use our interaction Rainfall Calculator (English units or Metric units)to find out exactly how much rain falls on your roof or yard, in your city block, or town.



When that rains, where does that go?

Once top top the land, rainfall either seeps right into the floor or i do not care runoff, i m sorry flows right into rivers and also lakes. What wake up to the rain ~ it falls depends on plenty of factors such as:

The price of rainfall: A many rain in a short duration tends to run off the land into streams quite than soak right into the ground.The topography of the land: Topography is the place of the floor -- the hills, valleys, mountains, and also canyons. Water falling on uneven soil drains downhill until it becomes component of a stream, find a hollow location to accumulate, favor a lake, or soaks into the ground.Soil conditions: there is a many of thick clay in the southeastern United states that rain has a tough time soaking into. Comparison that to the sandy soils in an ext desert areas, which enable water to quickly be absorbed, at least initially.Density that vegetation: It has actually long been well-known that plant development helps to decrease erosion brought about by flowing water. If girlfriend look in ~ hills there is no vegetation you"ll see gullies dug out by running water. Land through plant cover slows the rate of the water flowing on it and thus help to save soil from eroding.


Water Equivalents (approximate)

The following equivalents show the relationship in between the volume and also weight that water and between the volume and also speed of flow water.

Volume and weight

One customs of rain fall on 1 acre of ground is equal to about 27,154 gallons and also weighs around 113 tons.An inch of eye falling evenly on 1 acre of ground is identical to about 2,715 gallons of water. This figure, however, based upon the "rule-of-thumb" that 10 inch of snow is same to 1 customs of water, have the right to vary considerably, relying on whether the eye is heavy and also wet, or powdery and also dry. Heavy, wet snow has a really high water content—4 or 5 inches of this kind of snow contains around 1 customs of water. Thus, an inch of really wet snow over one acre might amount to more than 5,400 gallons the water, while an inch of powdery snow might yield only about 1,300 gallons.One acre-foot the water (the lot of water covering 1 acre to a depth the 1 foot) equates to 326,000 gallons or 43,560 cubic feet the water, and also weighs 2.7 million pounds.One cubic mile the water equals 1.1 sunshine gallons, 147.2 billion cubic feet, or 3.38 million acre-feet, and also weighs 9.2 trillion pounds (4.6 billion tons).

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Rate of flow (in a stream)

Water flowing at the steady rate of 1 gallon per minute is tantamount to: 1,440 gallons per day; 0.00223 cubic foot every second; 192.7 cubic feet every day; or 0.00442 acre-foot of water per day.Water flow at the steady price of 1 cubic foot per second is tantamount to: 449 gallons per minute; 646,000 gallons per day; 86,400 cubic feet per day; or 1.98 acre-feet that water per day.Water flowing at the steady rate of 1 acre-foot per day is equivalent to: 226 gallons every minute; 326,000 gallons per day; 0.504 cubic foot every second; or 43, 560 cubic feet the water per day.Water flow at the steady rate of 1 cubic mile every day is equivalent to: 764.6 million gallons per minute; 1.1 sunshine gallons per day; 1.7 million cubic feet per day; or 3.38 million acre-feet the water per day.