How much condensed liquid water is in a cubic mile of fog and clouds?

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How much condensed liquid water is in a cubic mile of fog and clouds?
Fog #1
Fog envelopes the Milwaukee Art Museum, on Lake Michigan’s shores. By I love Milwaukee

Fog is composed of tiny water drops, each with a diameter of about one-one thousandth (0.001) of an inch. They are small and fairly uniform in size. You would also find about one of these drops in each cubic inch of fog. So, if you do the math, that is about 56,000 gallons of water per cubic mile of fog. Given that each gallon of water weighs a bit over 8 pounds, that’s about 450,000 pounds of water — a lot of water!

How does that compare to clouds? A large cumulus cloud that you might find on a nice summer day contains about 1 million pounds of water drops. A thunderstorm cloud contains enough water drops to fill approximately 275 million gallon jars — about 1.1 million tons of water. To see that much water fall over Niagara Falls, you’d have to watch for six minutes. If that thunderstorm produces one inch of rain over one square mile, that is 17.4 million gallons of water weighing about 72,000.

A hurricane has about 250 million tons of water! How does that much water stay up in the atmosphere? The key is to remember that the water takes the form of tiny drops, not gallon jugs. Updrafts in the cloud can suspend these drops in the atmosphere.

Steven A. Ackerman and Jonathan Martin are professors in the Department of Atmospheric and Oceanic Sciences at UW-Madison, are guests on the Larry Meiller‘s WHA-AM radio show the last Monday of each month at 11:45 a.m.