Clouds are heavier than you think: Weight compared to elephants, trucks, and towers
Clouds, though often associated with lightness, are far from light. Physicists know how to determine their mass accurately. Despite their heaviness, clouds don't fall to the ground.
Even though clouds in the sky appear as light, fluffy puffs, they are heavy objects made of water. Their mass varies depending on the type of cloud, which is influenced by their density and volume.
A Cumulus cloud has a density of 0.5 grams per cubic meter. To put this in perspective, there is about one drop of water per cubic meter of the cloud. A single cumulus cloud can have a volume close to one cubic kilometer.
Not so light after all
This translates to one cumulus cloud containing 550 tons of water. An African elephant weighs between 3 and 7 tons. To simplify, a single cloud could weigh as many as a hundred elephants or about 12 fully loaded semi-trailer trucks.
Cumulonimbus clouds, or rain clouds, are significantly denser and larger. These clouds can be several miles tall and around 6-12 miles wide. Assuming a cumulonimbus cloud is nearly circular with a diameter of 6 miles, its volume would be approximately 188 cubic miles. Assuming the water density in this type of cloud is about 2 grams per cubic meter, the calculations change considerably.
The cloud weighs as much as 150 Eiffel Towers
Under these conditions, the mass of a cumulonimbus cloud is about 1.65 million tons. This is an unimaginable mass. To visualize, consider that the Eiffel Tower weighs about 11,000 tons. This means one rain cloud weighs as much as 150 Eiffel Towers. A rain cloud can weigh as much as ten fully loaded container ships.
The lightest clouds are cirrus clouds, with only a few grams per cubic kilometer densities. These clouds do not cause rain.
Why don't clouds fall to the ground?
Despite their heaviness, clouds do not fall. This phenomenon is related to the size of individual droplets sustained by air resistance. For water droplets, the terminal velocity of air, which allows clouds to stay afloat, is between 19 and 28 mph. Updrafts prevent these droplets from falling to the ground.
