On Friday, Hurricane Florence made landfall in North Carolina. It was also downgraded to a Category 1 storm: Its high winds, while still “extremely dangerous,” are no longer the storm’s scariest trait.
But then again, they never were.
Florence’s main threat has always been the water. In the coming days, Florence will besiege the Carolinas through two different mechanisms: First, it will inundate the coastline with powerful and deadly storm surge. Second, it will drop trillions of gallons of water across the region, from the barrier islands to the Appalachians, overwhelming dozens of rivers and creeks and initiating 1,000-year floods.
Florence, in a way, is a double threat, combining hurricane hazards new and old. Storm surge has long been dangerous: Historically, it has caused about half of all hurricane-related deaths in the United States. But recently, immense and slow-moving storms—like Hurricane Harvey—have dumped so much rain that they trigger devastating floods far inland.
Both of these dangers are likely made worse in Florence by the unique geography of the Carolinas and by the effects of human-caused climate change. The warming planet seems to amplify hurricanes’ water-related dangers more directly than it intensifies their high winds.
Take storm surge, for instance.
Storm surge is always caused by a hurricane’s huge area of high winds, which pick up ocean water and push it in the direction of the storm. As the hurricane approaches the coast, this excess ocean travels with it, literally displacing the sea onto the land. Even a few feet of storm surge can make for an unsurvivable situation, as this remarkable visualization from the Weather Channel makes clear:
This @weatherchannel visualization of storm surge is an amazing and sobering use of technology to show what hurricanes like Florence can do pic.twitter.com/fuszIcOR3s
— Brian L Kahn (@blkahn) September 13, 2018
Source:: The Atlantic – Science