Hurricane Florence weakened but far from weak: What to know about storm's power

Hurricane Florence weakened late Wednesday night to a Category 2 storm.

This hurricane, though, is far from weak.

Even in downgrading Florence, which is expected to crash into the Carolinas late Thursday night or early Friday, the National Hurricane Center predicted “life-threatening storm surge,” “catastrophic flash flooding and prolonged significant river flooding,” and “damaging hurricane-force winds.”

Here’s why the Saffir-Simpson Hurricane Wind Scale shouldn’t be the only measure of Florence’s strength:

This is a big hurricane

Hurricane Florence is bigger than the state of North Carolina and four times larger than Ohio. It would swallow the smaller New England states.

As of Wednesday night, Florence’s tropical-storm-force winds were nearly 400 miles wide – or the roughly the equivalent of driving from Washington, D.C, to Charlotte, North Carolina; or from Milwaukee, Wisconsin to St. Louis; or from Los Angeles to San Francisco.

The hurricane’s immensity is why about 10 million people across North Carolina, South Carolina and Virginia are under storm watches and warnings, with meteorologists projecting Florence could become the most powerful storm to hit this part of the United States in at least 25 years.

Harvey-level rain

The National Weather Service is predicting “excessive” rainfall totals, potentially up to 40 inches in isolated areas, as Florence comes to crawl off the coast of the Carolinas before making landfall somewhere near the border of the two states.

From Thursday night through Sunday morning, CNN reported that Florence would travel only 150 miles, or slower than the average walking pace of 2-3 mph.

Florence could threaten the largest rainfall event in U.S. history, Hurricane Harvey, the 2017 whirlwind that settled over Texas and dropped more than 60 inches of rain, turning roadways into rivers, destroying homes and buildings and killing nearly 90 people.

It was estimated that Harvey dropped the equivalent of 19 trillion to 21 trillion gallons of water in the greater Houston area, or, as The Washington Post reported a year ago, enough water to fill Utah’s Great Salt Lake four times.

Monster waves

The NHC measured wave heights of up to 83 feet – the equivalent of a seven-story building – as Florence churned in the Atlantic Ocean on Wednesday.

The waves will meet resistance as Florence approaches landfall, but storm surges up to 13 feet are expected in some areas of North Carolina, according to the weather service.

“The deepest water will occur along the immediate coast in areas of onshore winds, where the surge will be accompanied by large and destructive waves,” the NWS report said.

The deadliest and most destructive element of any hurricane, the storm surge from Florence could flood tens of thousands of structures, North Carolina Gov. Roy Cooper said.

Power outages

Duke Energy, a primary power supplier in the Carolinas,  already is warning that up to 75 percent of its 4 million customers could lose power – and not just for a few hours.

“We’re talking about days, potentially weeks,” Duke Energy spokesman Jeff Brooks said Wednesday night on CNN.

Bye-bye Florence?

Not every hurricane has its name retired – and there’s already a buzz that Florence will join the likes of Hazel (1954), Hugo (1989), Fran (1996) and Isabel (2003), the four most destructive hurricanes to strike the southeastern United States.

Names are retired only “if a storm is so deadly or costly that the future use of its name on a different storm would be inappropriate,” according to the National Ocean and Atmospheric Administration website.

Doesn’t sound like a weak hurricane, does it?