The water started rising in Ocracoke around 8 a.m. And for two agonizing hours, it didn’t stop.
The National Weather Service in Newport, N.C., issued a flash flood emergency Friday morning for the Outer Banks, citing “rapid water level rises on the eastern portion of Pamlico Sound resulting from Hurricane Dorian.” The ocean climbed 7.16 feet in just over two hours as the eye of the storm moved off the coast, turning winds north-northwesterly, and sending salt water spilling over roadways and rushing into homes.
Photos emerged on social media showing water as high as the tips of fence posts, with the stoop of a home completely submerged. Other images depict residents wading through chest-high water, and homes and businesses were inundated as well.
The area had been under a storm-surge warning for almost 48 hours, beginning Wednesday morning, calling for a 3- to 5-foot surge. The U.S. Coast Guard tidal station at Hatteras, N.C., recorded its second-highest water-level maximum on record; however, the station was erected in 2010, meaning its records are not extensive. The record was claimed by Hurricane Matthew in 2016.
But what suddenly flooded Ocracoke was abrupt surge coming from Pamlico Sound. This water rose immediately after the eyewall tracked overhead. The data shows a textbook situation, in which shifting winds sent a slosh of water eastward when the winds switched direction.
Weather observations reveal the abrupt drop in wind and air pressure as the eye passed by, along with the winds that howled again immediately thereafter and gusted as high as 90 mph. At the same time, winds switched from the east to the northwest, which effectively piled water up against the eastern edge of Pamlico Bay, spilling over the barrier islands. Radar reveals the Category 1 eyewall pummeling Ocracoke at that time with strong offshore winds.
Generally, the National Weather Service does not issue flash flood warnings for saltwater flooding. However, in rare instances, it can be a lifesaving option when water levels are expected to rise rapidly. That’s because flash flood warnings can trigger the Emergency Alert System, causing your cellphone to emit that shrill squeal you’ve probably heard during other severe weather events.
On Thursday, residents of the Outer Banks gawked at “missing” water, which exposed new dry ground, as Dorian’s initially northeasterly winds pushed the water in the sound to the west.
As the leading edge of the eyewall moved through Friday morning, winds swept water away from the coast.
The sudden return of water was well forecast by meteorologists, who warned of imminent flooding when the winds switched direction and increased in speed Friday morning.
As of 10:30 a.m., the water levels were beginning to slowly recede.