A complex of slow-moving thunderstorms dropped tornadoes and extreme rainfall across Broward County in Florida this week, causing historic flooding that forced residents to abandon vehicles and scramble to higher ground. A back-of-the-envelope calculation suggests the rainfall totals across the county from that downpour amounted to roughly 88 billion gallons.
That would equate to 738 billion pounds of moisture, or roughly 370 million tons — most of which originated from a humid easterly wind blowing from the Bahamas.
The excessive rainfall, which fell at rates briefly topping six inches per hour, was a product of slow-moving thunderstorms anchored atop a stalled frontal boundary. The initially unanticipated deluge stemmed from the natural randomness of the atmosphere, but it fits into a pattern of a warmer, wetter world with higher rainfall rates.
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Statistically, the episode easily qualifies as a thousand-year rain event — or one that would have a 0.1 percent chance or less of occurring in any given year.
Share this articleShareApproximately a third of the city’s average annual rainfall came down during an eight-hour window. With reports of up to 25.91 inches at Fort Lauderdale-Hollywood International Airport, the event obliterated the previous record for wettest calendar day, which was 14.59 inches, set April 25, 1979.
Visualizing the rainfall
Using a rough methodology of contouring how much rain fell across Broward County on Wednesday, according to National Weather Service data, we can estimate the rainfall as totaling approximately 88 billion gallons. That is equal to:
- 129 times the volume of the Great Pyramid of Giza.
- 134,120 times the volume of an Olympic-size swimming pool.
- Three months of residential water consumption in New York City.
- The drinking water consumed by the entire U.S. population in 1.46 years.
- 5.5 hours’ worth of discharge from the Mississippi River.
Alternatively, we can talk about how much all that water weighed. Its weight was equivalent to:
- 56 million male African bush elephants.
- 36,500 Eiffel Towers.
- 13,600 Statues of Liberty.
Apropos to volume, all the water that had fallen on Broward County by late Wednesday could be gathered into a massive cube 0.43 miles wide per side.
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