After unleashing catastrophic wind and rain in the Bahamas, a powerful Hurricane Dorian moving northwestward Tuesday threatens to bring damaging winds, life-threatening storm surge and flash flooding to Beaufort County starting Wednesday.
The National Weather Service issued hurricane and storm surge warnings for the Hilton Head Island, Beaufort and Bluffton areas Tuesday in anticipation of Dorian, still expected to be a Category 2 hurricane as it passes off the Lowcountry coast late Wednesday through Thursday.
A storm surge warning means there is a “danger of life-threatening inundation, from rising water moving inland from the coastline within the next 36 hours,” according to the National Weather Service. A hurricane warning means the area should expect hurricane conditions within the area in the next 36 hours.
“We’re expecting the worst conditions late Wednesday into early Thursday, and tailing through the day on Thursday,” meteorologist Sarah Johnson of the National Weather Service in Charleston said.
Small or significant changes?
Ron Morales, warning coordination meteorologist at the NWS in Charleston, said Tuesday evening that the storm’s track has shifted slightly westward, causing the hurricane watch to change to a hurricane warning.
“Small changes in the track would result in significant changes in wind, storm surge inundation and heavy rainfall impacts,” the NWS in Charleston reported.
Beaufort County should expect tropical-storm force winds at 8 a.m. Wednesday at the very earliest, but most likely by 8 p.m Wednesday, according to the National Hurricane Center.
Because the wind field of the storm is smaller in comparison to most Atlantic hurricanes — with tropical storm-force winds extending 175 miles from the center, and hurricane-force winds 60 miles from the center — meteorologists are focusing on where the storm takes a northern turn somewhere parallel to the Florida-Georgia line Wednesday and another northeastern turn when it’s closer to the Savannah River.
“The wind fields could expand or contract as it moves up the coast,” Johnson said. “That’s why we’re really watching where it turns. There is still a lot of uncertainty, depending on where those turns occur.”
The “cone of uncertainty” is a five-day outlook based on historical data projecting a 60-70 percent chance the tropical cyclone will remain within the track during that time frame.
Considering that one-third of hurricanes fall outside of these projected cones, it’s important to note that Dorian’s projected path is still widely unknown.
“We still can’t rule out a landfall ( in South Carolina) or a closer approach to the coast,” Ron Morales, warning coordination meteorologist at the NWS in Charleston, said Tuesday.
What to expect
Beaufort County should prepare for hurricane-force winds, heavy rain, freshwater flooding and storm surge from Wednesday night through Thursday.
“The primary threat for Beaufort County is the storm surge,” Neil Dixon, NWS meteorologist, said.
A life-threatening storm surge of 4-7 feet above ground in certain coastal areas is expected starting Wednesday morning, the NWS said.
“Those storm surge levels could be similar to Matthew or Irma, or worse,” Morales said.
The storm surge could make roads in coastal Beaufort County impassable and severely erode the barrier island beaches.
“What’s particularly dangerous is that people think storm surge is just the beaches,” Dixon said. “What they don’t realize is the water will have enough time to build into every tidal creek and river, and the higher the storm surge builds, the less effective the storm drains will become, and that will cause flash flooding.”
Wind is also a big concern for forecasters, Dixon said.
Latest projections at 2 p.m. show a 5 to 20 percent chance of hurricane-force winds lasting over a minute in the next five days throughout Beaufort County. Dixon said those models should increase Wednesday.
Hurricane-force wind gusts of 74-110 mph are more likely on the barrier islands, including Hilton Head and Hunting islands. Those hurricane-force gusts could bring widespread power loss, significant tree damage and minor structural damage along the coast, Morales said.
“Prepare for considerable wind damage,” the NWS in Charleston reported Tuesday, warning that Beaufort County should be ready for life-threatening wind equivalent to a Category 1 or 2 hurricane, depending, again, on those turns. However, the threat for tornadoes is relatively low.
Heavy rainfall and freshwater flooding are also a concern for Beaufort County, especially east of I-95, the NWS in Charleston reported Tuesday morning. Meteorologists are particularly concerned that heavy rainfall could combine with storm surge inundation to create flash flooding in the Lowcountry.
Beaufort County could see 4-8 inches of rain from Wednesday to Thursday, with higher amounts near the coast, according to the latest forecast.
As of 6 p.m. Tuesday, Dorian was moving at 6 mph, up from this morning’s 1 mph movement, with sustained wind speeds of 110 mph. The storm is projected to speed up within the next 48 hours, the National Hurricane Center said.
“It’s a very, very challenging forecast,” Dixon said. “It could be dangerously close to the South Carolina coast, anywhere between Hilton Head and the Grand Strand.”
Local officials encourage evacuation
Local government officials and law enforcement are encouraging Beaufort County residents to evacuate if they can.
“Dorian is still a serious storm,” Sheriff P.J. Tanner said in a Beaufort County Sheriff’s Office press conference Tuesday morning. “We expect some impact here in Beaufort County. ... We hope for the best, but we’re prepared for it.”
Beaufort County is still under an evacuation order, but lane reversals on Hilton Head have ended.
Dixon said if anyone is considering evacuating, do it before Wednesday morning.
“Dorian is going to cause storm surge,” Dixon said. “People shouldn’t wait until (Wednesday) to leave. Waters will rise at day break and evacuation routes could be cut off.”
The swing bridges in the county, controlled by S.C. Department of Transportation, will be closed to marine traffic beginning at 7 p.m. Tuesday, said Neil Baxley, commander of the Sheriff’s Office Emergency Management. Vehicles will still be able to use the bridges.
EMS crews were to be pulled from Daufuskie Island at 5 p.m. Tuesday, Beaufort County administrator Ashley Jacobs said at the press conference.
Hilton Head’s bridges will not close unless the Beaufort County Sheriff’s Office determines that the winds will make traveling across them dangerous, the Town of Hilton Head Island said in a news release.
No curfews had been set in Beaufort County as of Tuesday morning, but Tanner said officials are “having discussions now” about whether to enact one. He said he hopes any curfew would be uniform countywide.