As Hurricane Florence moves ashore, much attention was given to its decreased intensity, dropping from a Category 4 to a Category 2 hurricane. Any consolation taken from that, however, is misplaced. Florence is hitting the Carolinas with a colossal, almost unimaginable storm surge:
Storm surges aren't walls of water, like a tsunami, as commonly thought. Caused by a hurricane's winds pushing relentlessly on the shore, they are more like domes of high water that form as the ocean spreads inland. The high water has destructive waves on top, and it comes in addition to normal tides.
"You are taking the ocean and raising it," said storm surge expert Hal Needham, director of Marine Weather and Climate in Miami. "It's not a wave the surfer rides. It's actually raising the ocean. That's why it's so scary."
Florence's storm surge will probably be 7 to 11 feet above ground in parts of North Carolina, according to the National Hurricane Center. Other areas can expect the surge to be taller than the average person — nearly 6 feet or higher.
Erika Navarro at The Weather Channel provided this animated simulation of what a 6-9ft. storm surge would represent for an inhabited area:
The hazards are not limited to the shoreline communities:
It's not just beach areas that are at risk. Storm surge invades rivers and estuaries, too. And National Hurricane Center Director Ken Graham said that's a particular worry with Florence.
"These bays, these rivers and these inlets, there's so much storm surge the water is being literally forced to flow the opposite direction," Graham said. "You can get storm surge even several miles inland."
While hurricane-force winds can rip the roofs off houses, it is the water — storm surge, inland flooding, surf and drowning at sea — that kills nearly 9 out of 10 people in hurricanes like Florence.
Friday, Sep 14, 2018 · 12:09:36 AM +00:00
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ian douglas rushlau
The Weather Channel provided this detailed summary of local and regional storm surge effects:
Here are the latest storm-surge inundation forecasts from the National Hurricane Center if the eye of Florence arrives at high tide:
- Cape Fear to Cape Lookout, North Carolina, including the Neuse, Pamlico, Pungo and Bay rivers: 7 to 11 feet, with locally higher amounts possible
- Cape Lookout, North Carolina, to Ocracoke Inlet, North Carolina: 6 to 9 feet
- South Santee River, South Carolina, to Cape Fear, North Carolina: 4 to 6 feet
- Ocracoke Inlet, North Carolina, to Salvo, North Carolina: 4 to 6 feet
- Salvo, North Carolina, to the North Carolina/Virginia border: 2 to 4 feet
- Edisto Beach, South Carolina, to the South Santee River, South Carolina: 2 to 4 feet