Authorities said 19 people were hurt after a late-night rush near a stage area in Atlantic Beach sparked a mass casualty response. ATLANTIC BEACH, S.C. — Nearly 20 people were injured after a crowd surge at a gathering in coastal South Carolina early Sunday, authorities said. Emergency crews responded around 1 a.m. to reports of what officials described as a “stampede incident” near a stage area in Atlantic Beach, according to Horry County Fire Rescue. This story continues below. First responders found 19 people hurt in the rush, though officials said none of the injuries appeared to…