From an article by Scott Granneman in Securityfocus (on Virtualization for Security):
As I watched the storm approach, I thought about one of the most fascinating bits of weather trivia I ever heard: the weight of rain clouds in terms of elephants [ABC has unfortunately removed the 2003 news article - Ed.].
Every cloud is made up of moisture, of course. On a day like today, a single fluffy cloud contains about 550 tons of water. Your average elephant weighs about six tons, so that means that those happy spring clouds are equivalent to around 100 elephants.
A bigger storm cloud, more like the one I saw barreling into the area recently, is more like 200,000 elephants in terms of weight. That's quite a jump, and it's kind of humbling, funny, and awesome to think of 200,000 elephants stampeding across the sky.
No such emotions attach to the numbers associated with a hurricane, however. Instead of awe or humor, now we're talking absolute terror. Instead of 100 elephants, or even 200,000 elephants, the water in a hurricane is equivalent to 40,000,000 - yes, forty million - elephants. Forty million elephants in the sky, bringing destruction and fear. Forty million elephants.
Next time you look at a cloud, think about how many elephants are in it. You had no idea that a cloud was so massive, and no idea that a creature so huge and seemingly earth-bound can be used to understand something so apparently light and ephemeral, did you?