Q: How much condensed liquid water is in a cubic mile of fog?
A: Fog is composed of tiny water drops, each one with a diameter of about one-one thousandth (0.001) of an inch. They are small and fairly uniform in size. You also would find about one of these drops in each cubic inch of fog.
If you do the math, that is about 56,000 gallons of water in one cubic mile of fog.
Given that each gallon of water weighs a bit over 8 pounds, that's about 450,000 pounds of liquid water. That is a lot of water. How does that compare to other clouds?
A large cumulus cloud that you might find on a nice summer day is made up of about 1 million pounds of water drops.
A thunderstorm cloud contains enough water drops to fill up approximately 275 million gallon jars. That's about 2.3 billion pounds, or 1.1 million tons of water. To see that much water fall over Niagara Falls, you'd have to watch the falls for six minutes.
If that thunderstorm produced one inch of rain over one square mile, that would be 17.4 million gallons of water weighing 143 million pounds (about 72,000 tons).
A hurricane has about 250 million tons of water swirling in the storm. How does that much water stay up in the atmosphere?
The key is to remember that the water is in the form of tiny drops, not gallon jugs. The rising motion in the cloud is able to keep these drops suspended in the atmosphere.
Steven A. Ackerman and Jonathan Martin, professors in the UW-Madison department of atmospheric and oceanic sciences, are guests on WHA radio (970 AM) the last Monday of each month at 11:45 a.m.