Does a cumulus cloud really weigh a million pounds?

GRAND RAPIDS, Mich. ( WOOD ) — Just because something floats doesn’t mean it is weightless. A great example is when oil is poured onto water. The oil will float on top of the water, but that doesn’t mean it has no weight.

Clouds are made of water and air, both of which have weight. Air currents and physical properties help keep clouds suspended in the air. Water vapor particles are incredibly small, helping with the suspension. Air molecules fill the atmosphere, and each has a mass. In fact, at sea level, one square inch of surface area has about 14.5 pounds of weight pushing down on it from the air above.

Clouds are saturated parcels of air. Water molecules also have weight. One molecule of water is estimated to weigh 3 x 10^-23 grams. A whole cloud full of water molecules can add up fast.

If a cloud were exactly 1 km cubed in volume, there would be enough water molecules inside a cloud to add up to more than 1.1 million pounds. And that’s just water weight.

If the physical calculations are done to include air molecules in the weight and reduce the limitations on the size of a cumulus cloud from the 1 km parameters, the numbers are even more staggering.

Thunderstorms are even heavier as they contain rain and hail. Cirrus clouds are much lighter as they contain ice crystals.

Even though the entire cloud collectively is quite heavy, it is a comfort to know that in comparison to the column of air vertically stacked in the sky above you, it is lighter than the dense concentration of air right at the surface.

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