Florence's rain total will likely be staggeringly huge.
Meteorologist Ryan Maue of weathermodels.com calculates that Hurricane Florence is forecast to dump about 18 trillion gallons of rain over a week over the North Carolina, South Carolinas, Virginia, Georgia, Tennessee, Kentucky and Maryland. It doesn't include rain after it dissipates and its remnants circle back to the northeast.
That much rain is 2.4 trillion cubic feet (68 billion cubic meters). It's enough to cover Manhattan with nearly 3,800 feet (1.1 kilometers) of water, more than twice as high as the island's tallest building, One World Trade Center.
Florence's 18 trillion gallons is as much water as there is in the entire Chesapeake Bay. It's also enough to cover the entire state of Texas with nearly 4 inches (10 centimeters) of water.
North Carolina alone is forecast to get 9.6 trillion gallons of rain, enough to cover the Tar Heel state in about 10 inches (25 centimeters) of rain.
Those rainfall predictions still don't quite measure up to the 25 trillion gallons from last year's Harvey in Texas and Louisiana because the 2017 storm stalled longer and stayed closer to the Gulf of Mexico for more moisture. Florence still should swamp the 5.2 trillion gallons that fell 19 years ago when Floyd was the last scary storm to hit the Carolinas.
Maue calculates that 34 million people in the U.S. are forecast to get at least 3 inches (7.6 centimeters) of rain from Florence, with more than 5.7 million probably getting at least a foot, and about 1.5 million getting 20 inches (51 centimeters) or more.
Explore further: For meteorologists, Florence 'is a horrific nightmare storm'