by The Old Scot
Try to imagine life without clouds. Would there be creeks and rivers? Would there be trees, and fields of growing corn and hay? Would there be anything green on earth at all? Would you and I be here? Quite simply, "No!"
God created a wondrous continuing miracle when He set up our planetary weather system. Without clouds, water would cover more than 85 per cent of the globe—but it would all be in the oceans. Dry land would be very dry indeed! Without clouds there would be no way for the water to get where we need it.
Rain begins as invisible water vapor, which is absorbed into the air from lakes, rivers and oceans by a process called "evaporation." Besides drying clothes hanging on clothes lines, evaporation is capable of turning more than 5,000 tons of water into water vapor from each square mile of ocean in just one hour, around the globe.1 That is a lot of water! But it takes a lot of water to fuel our world's cloud system!
Invisible water vapor has to become droplets of water before it can form into clouds. These droplets may be so tiny that eight million of them would only make one full-grown drop of rain. But the droplets cannot form unless they have a speck of solid matter to condense around—such as dust, ash, smoke particles, or even polluting chemicals which cause "acid rain."
Billions upon billions of these water droplets are what form clouds, and the clouds are able to float in the air for many hundreds of miles, until conditions are just right for them to release some of their moisture as rain, snow, sleet, or hail.
What causes rain? Rain occurs when clouds can no longer hold their full load of water. This usually happens when a cloud cools. Cool clouds can't contain as much moisture as warm clouds. That is why, for instance, it is likely to rain when a cold front runs into a warm front.
Let's view the process from space: We see clouds forming over the huge Pacific Ocean, and then marching in ragged formation, but always east, because of the earth's rotation. As these bands of clouds reach land—and especially mountains—they are forced higher, and as they climb they hit colder air. Hey presto, it starts to rain!
As the prevailing winds carry the clouds ever onward, and they not only still carry a lot of moisture, but can also renew their supply by evaporation from lakes, rivers, and wet earth. Invasions of cold air from the north are just as capable as mountains of cooling the clouds and so producing rain. Also, fresh supplies of water vapor may arrive from elsewhere (the Gulf of Mexico, for instance) and cause more rain.
Of course, clouds do more than just bring rain. They also provide invaluable shade, and thus help keep the earth from baking under the hot sun. And they bring a great deal of beauty. Who has not been awed by the sight of magnificent summer thunderheads? Or delighted in a glorious sunset? (It wouldn't amount to much without clouds.)
Yes, we have much to thank God for. Every time we see a cloud in the sky, we are witnessing one of His blessings.
1. Water: Miracle of Nature, Thomson King, Macmillan Co., NY, 1953, pp. 63-64, 78.
2. The Air Around Us, John Sparks, Danbury Press (Div. Of Grolier Enterprises), 1975.