Rain and also snow are an essential elements in the Earth"s water cycle, i m sorry is crucial to every life top top Earth. Rainfall is the main way that the water in the skies comes down to Earth, wherein it fills our lakes and rivers, recharges the secret aquifers, and also provides drinks to plants and animals.

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A localized hefty summer rainstorm in Colorado

Here is a classic summer rainstorm; they space often little but intense. Other rain events are more "frontal" in nature, with large nimbostratus varieties of clouds happen precipitation over a large area. 

Credit: Howard Perlman, gimpppa.org

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

The lot of precipitation that falls roughly the human being may selection from much less than 0.1 customs per year in some deserts to more than 900 inches every year in the tropics. One of the driest point out on earth is Iquique, Chile, where no rain dropped for 14 years. The world"s wettest spot, Mawsynram, in Northeastern India, experienced a median of 494 customs of rain a year throughout the year 1989-2010, instead of the vault placeholder, Cherrapunji, also in Northeastern India, where a typical of 471 inches fell throughout the exact same period.

In situation you"re wondering, the wettest ar in the unified States, as displayed by data collected by the Western local Climate Center, is top top Mt. Waialeale, Hawaii, whereby an average of 373 customs of rain has fallen annually in between the years 1949 and also 2008. Mt. Waialeale also experienced more than 642 inches of rain native July 1947 come July 1948! If you think that"s something, Cherrapunji holds the single year document of 905 customs measured in 1861!

By contrast, the conterminous (the 48 "lower" states) United claims receives sufficient precipitation throughout an typical year come cover the states to a depth of around 30 inches. This is tantamount to around 1,430 cubic mile of water every year. What wake up to the water after the reaches the ground counts upon plenty of factors such as the price of rainfall, topography, floor condition, thickness of vegetation, temperature, and the degree of urbanization.


Wide spread out flooding in Lithia Springs, Georgia simply west the downtown Atlanta, after epos rainfall, 22 Sept. 2009. Impervious surfaces and urban buildup reasons rainfall come runoff much quicker, and also with better flooding consequences, throughout heavy rains.

Credit: NASA

For example, the direct runoff in a highly urbanized area is fairly great, no only since of the thickness of roofs and impermeable pavements permits less rain come infiltrate the ground, but likewise because storm-sewer systems carry an ext water directly to the streams and also lakes. In a more natural or undeveloped area, the straight runoff would be considerably less.

In the unified States, an median of some 70 percent of the annual precipitation return to the atmosphere by evaporation native land and also water surfaces and by transpiration native vegetation. The continuing to be 30 percent eventually reaches a stream, lake, or ocean, partially by overland runoff during and immediately after rain, and partly by a lot slower path by relocating though the ground.

Much the the rain the enters the ground filters down into subsurface water-bearing rocks (aquifers) and eventually get lakes, streams, and rivers wherein these surface-water bodies intercept the aquifers. The portion of the precipitation that reaches the streams produces an average yearly streamflow in the United says of about 1,200 billion gallons a day. Through comparison, the Nations"s homes, farms, and factories withdraw and use around 355 billion gallons a work (2010).


Amount that water received once an inch of rain occurs

Have you ever wondered how much water falls onto your yard during a rainstorm? utilizing a 1-inch rainstorm together an example, the table below gives instance of exactly how much water falls during a storm for assorted land areas.


AreaArea (square miles)Area (square kilometers)Amount the water (gallons)Amount of 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 how much rainwater some cities may receive throughout a year. Because that example, Atlanta, Ga. Averages around 45 inch of precipitation every year; multiplying this through the 2.293 exchange rate gallons shown in the table together the number of gallons in 1 customs reveals that part 103.2 exchange rate gallons that water fall on Atlanta in an typical year. In a city the dimension of Atlanta, the every capita water use is about 110 gallons every day or 40,150 gallons per year. Thus, the water indigenous a year"s precipitation, if it might be collected and save on computer without any type of loss, would certainly supply the requirements of about 2,574,000 people.




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



When the rains, whereby does that go?

Once ~ above the land, rainfall either seeps into the soil or i do not care runoff, i m sorry flows right into rivers and also lakes. What wake up to the rain after it drops depends on numerous factors such as:

The price of rainfall: A the majority of rain in a short period tends to run off the land right into streams rather than soak right into the ground.The topography of the land: Topography is the place of the soil -- the hills, valleys, mountains, and also canyons. Water falling on uneven land drains downhill till it becomes component of a stream, finds a hollow place to accumulate, favor a lake, or soaks into the ground.Soil conditions: over there is a many of thick clay in the southeastern United states that rain has actually a hard time soaking into. Contrast that to the sandy soils in an ext desert areas, which permit water to conveniently be absorbed, at the very least initially.Density that vegetation: It has actually long been recognized that plant expansion helps decrease erosion led to by flowing water. If girlfriend look in ~ hills there is no vegetation you"ll check out gullies dug the end by to run water. Land with plant cover slows the rate of the water flowing on it and thus helps to store soil indigenous eroding.


Water Equivalents (approximate)

The complying with equivalents show the relationship between the volume and weight the water and between the volume and speed of flow water.

Volume and weight

One inch of rain fallout’s on 1 acre of ground is equal to around 27,154 gallons and also weighs around 113 tons.An customs of snow falling same on 1 acre of ground is equivalent to around 2,715 gallons of water. This figure, however, based ~ above the "rule-of-thumb" the 10 customs of eye is equal to 1 inch of water, deserve to vary considerably, depending upon whether the snow is heavy and also wet, or powdery and also dry. Heavy, wet snow has a very high water content—4 or 5 customs of this type of eye contains about 1 customs of water. Thus, an customs of really wet snow over one acre could amount to more than 5,400 gallons of water, when an customs of powdery snow could yield only around 1,300 gallons.One acre-foot of water (the quantity of water spanning 1 acre come a depth that 1 foot) equates to 326,000 gallons or 43,560 cubic feet that water, and also weighs 2.7 million pounds.One cubic mile of water amounts to 1.1 trillion gallons, 147.2 exchange rate cubic feet, or 3.38 million acre-feet, and weighs 9.2 trillion pounds (4.6 billion tons).

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Rate of flow (in a stream)

Water flow at the steady rate of 1 gallon every minute is indistinguishable to: 1,440 gallons per day; 0.00223 cubic foot per second; 192.7 cubic feet per day; or 0.00442 acre-foot the water every day.Water flow at the steady rate of 1 cubic foot per 2nd is equivalent to: 449 gallons every minute; 646,000 gallons every day; 86,400 cubic feet every day; or 1.98 acre-feet that water every day.Water flow at the steady price of 1 acre-foot per day is identical to: 226 gallons every minute; 326,000 gallons per day; 0.504 cubic foot every second; or 43, 560 cubic feet the water every day.Water flowing at the steady rate of 1 cubic mile per day is equivalent to: 764.6 million gallons per minute; 1.1 sunshine gallons every day; 1.7 million cubic feet per day; or 3.38 million acre-feet of water every day.