When I look at one of those big old cumulus clouds, I sometimes find myself wondering just how big it is. Looks pretty darn big, but as I have no frame of reference, I can’t get much more specific than that. Can anyone help me out? What would be the dimensions of a good-sized cumulus cloud?
And when the sky is covered with high-altitude clouds and you look from one horizon to another, how large an expanse of clouds are you seeing?
Looking at clouds with mountains near to them should give you a good idea, if you know how big the mountain is. 2-5 miles across the base is probably about right. I have seen small puffs of cloud that were only slightly larger than my airplane, so 50 feet or so.
For the high altitude, such clouds can be at different hights, so it will vary as well, but as a rough approximation figure you are on the horizon for the cloud at the limit of what you can see.
Use 20,000 feet for a low cirrus cloud, and this diagram:
would show those clouds as 110 miles away. A circle of 110 miles radius would be about 38,000 square miles.
A thunderstorm will reach right up through the tropopause sometimes which means they can be around 50,000 feet high in the tropics. The high level “anvil” that forms at the top of a thunderstorm may spread over a hundred miles while the body of the cloud at low level is much smaller and may be about 5 - 10 miles across. (I don’t mean for those numbers to be limiting, some large supercells are much larger than 10 miles.)
Other types of cloud can spread over vast areas. A layer of stratus will form over as large an area as conditions permit.
Didn’t Cecil answer a similar question years ago? I think somebody asked if a cloud weighs more or less than a 747 jetliner. The answer was that the cloud does indeed have more mass than the airplane. (There was also some pedantic discussion on the weights of the cloud and the plane being zero, because they’re up in the air.)