Will the Hilton Head bridges close during Tropical Storm Debby? Here’s what SCDOT says

As a hurricane or tropical storm creeps toward Beaufort County , one particular question becomes a common refrain: Will the bridges close?

It’s a fair question in the Hilton Head Island area, where many residents’ homes and places of work are only accessible by bridge. Four bridges connect Hilton Head to Bluffton, and multiple others across the county connect St. Helena, Beaufort and Port Royal. In extreme weather, powerful winds and rising water levels can make traveling on bridges much more dangerous.

The South Carolina Department of Transportation has the final say in closing all bridges across the state. As of Monday afternoon, there were no bridge closures related to Tropical Storm Debby , according to an agency spokesperson.

SCDOT and other officials do not appear to have rigid criteria or specific benchmarks to close a bridge; instead, they “work closely with local emergency management and law enforcement officials” to determine when closures are necessary.

Asked during a Monday morning press conference if the Hilton Head bridges would close, Tom Dunn, the Town of Hilton Head Island’s emergency manager, had the same case-by-case attitude.

“We hope not,” Dunn said. “But yes, that is a valid possibility.” He added that if the bridges do close, “we’re prepared” with sufficient resources on the island until the highway is safe to cross.

Historically, the bridges to Hilton Head have remained open during most hurricanes and tropical storms, including Idalia , Ian , Florence and Michael . Even after Hurricane Dorian prompted a mandatory evacuation in 2019, the Cross Island Parkway stayed open — one lane of eastbound traffic was briefly switched to westbound as motorists evacuated the island en masse. About seven hours after the lane reversal, traffic resumed its normal flow .

When do wind speeds get dangerous?

Despite a lack of definitive standards for closing bridges, officials have previously indicated conditions that would likely shutter certain spans. The primary factor is wind: If it reaches sustained speeds of 30 mph, the Cross Island Parkway would “typically” be restricted to high-profile traffic such as emergency vehicles, an SCDOT official said last year . If winds exceeded 40 mph, all vehicle traffic would likely be blocked.

At sustained winds above 40 mph, most vehicles used by the Beaufort County Sheriff’s Office — Dodge Chargers and Ford Explorers — are unable to cross major bridges.

Luckily, winds associated with Tropical Storm Debby are unlikely to cross that threshold. In Beaufort County, the National Weather Service predicts the wind will be at its most powerful Tuesday , with sustained speeds of 20 to 30 mph throughout the day and potential gusts up to 40 mph.

As Hurricane Florence raged in 2018 , the Beaufort County Sheriff’s Office told reporters the Hilton Head bridges would only be closed if an evacuation with lane reversals was ordered. No such order came — but when Hilton Head was evacuated for Hurricane Dorian one year later, the bridges stayed open.

Due to its length and high clearance, the Talmadge Memorial Bridge over the Savannah River regularly closes for extreme weather, including during Hurricane Idalia last year. Officials in Georgia were “not expecting” to close the bridge unless conditions worsened, according to the Savannah Morning News .