The Brief A young girl remains missing after being swept into the ocean by a powerful wave at Treasure Island Beach in Laguna Beach on Tuesday evening. The disappearance occurred amidst a historic, long-period summer south swell generated off Antarctica-the largest seen in years-which is bringing massive waves to Southern California. While bystanders successfully rescued the girl's mother and sibling around 7:30 p.m., a multi-agency search continues under extremely hazardous coastal conditions. A massive multi-agency search is underway in Laguna Beach after a young girl was swept into the ocean by high surf on Tuesday evening. The disappearance coincides with a historic summer south swell slamming Southern California's coast, driving some of the largest and most dangerous waves seen in years. What we know: The incident happened around 7:30 p.m. Tuesday near Treasure Island Beach, according to the Orange County Sheriff's Department. High surf pounding Southern California beaches created dangerous conditions, producing a wave that swept a mother and her two children off the shoreline and into the ocean. Witnesses on the scene immediately intervened and successfully rescued the mother and one of the children. However, the second child, described as an adolescent girl, could not be reached and remains missing. The emergency response and ongoing search operations are being coordinated by several regional agencies, including the Laguna Beach Marine Safety Department, the Harbor Patrol of the Orange County Sheriff's Department, and the United States Coast Guard. The dangerous water conditions are being driven by a high surf event affecting both Orange and Los Angeles counties, with breaking waves reaching heights of up to 9 feet along the coast. What's next: What we don't know: The identity and exact age of the missing girl have not yet been publicly released by authorities. It is also currently unknown if the mother or the rescued sibling sustained injuries during the incident or required hospitalizati #foxla #crimewatchlosangeles