How Many Gallons of Water Fell over Parts of South Carolina?

Photo Courtesy: CNN.com

Some are calling this rain event a "Thousand Year Rain Event".



Many locations have received more than 20" of rain since Friday.  The final rainfall totals map here as of Tuesday 5:30am.

The National Weather Service office in Columbia, South Carolina has a great summary HERE. Eyeballing this map shows roughly seven counties with at least 15" across at least 90% of each county as of Sunday evening.

So how much rain in gallons is 15"?  A quick volume calculation will give us the answer: The area of the 7 county region (Richland, Sumter, Clarendon, Williamsburg, Berkeley, Calhoun and half of Charleston counties) is 10,317 square miles. Convert 15 inches into miles and you get 0.000237 miles. Multiply these together you get 2.44 cubic miles. Convert cubic miles into gallons and the answer is:

2,690,000,000,000 gallons (trillion)! 

This is DOUBLE the volume of Lake Okeechobee in Florida.

So image dumping Lake Okeechobee TWICE over these 7 counties over a 3 days period!