HILTON HEAD ISLAND, S.C. — People are leaving South Carolina’s barrier islands under a mandatory evacuation order as Hurricane Irma approaches Florida.

Highway Patrol Sgt. Bob Beres said Saturday morning “traffic is flowing” as residents evacuate.

Gov. Henry McMaster’s order Friday night required people on eight barrier islands along South Carolina’s southern coastline to leave beginning at 10 a.m. Saturday. The Republican governor says expected storm surges of up to 6 feet would bring “serious flooding” to those low-lying areas.

The most populous island being evacuated is Hilton Head Island in Beaufort County. Police barricades and cones are blocking entrance onto the island that’s home to about 40,500 people.

The Edisto Beach portion of Edisto Island is also being evacuated, as well as Harbor, Hunting, Fripp, Daufuskie, Tullifini and Knowles islands.