The city's Marine Safety Department responded to a 911 call about multiple swimmers in distress near Treasure Island Beach around 7:30 p.m. Tuesday. Officials say a mother and her two children were swept into the ocean by powerful water conditions near the shoreline.
Bystanders jumped into action and managed to rescue the mother and one of her children. An adolescent girl remains missing.
Video posted to social media shows the search efforts that quickly ensued, with first responders and boats in the water and helicopters circling overhead.
Those efforts continued into Wednesday morning as officials urged the general public to think twice before getting into the water. If you are not an expert swimmer, lifeguards say you should stay out of the water and stay safe on the sand.
Two of the bystanders who helped in the rescue were taken to the hospital in stable condition. The condition of the mother and child is unknown.
Massive swell brings historic waves
Many of the region's south-facing beaches are expected to have 5-to 8-foot waves, with high sets on tap at spots like Newport Beach's The Wedge, the world-famous surf break located at the southernmost tip of the Balboa Peninsula.
At The Wedge, the powerful south swell delivered historic sets on Tuesday with waves peaking at over 20 feet.
The Wedge in Newport Beach sees historic 20-foot waves
Meanwhile, video out of Malibu shows powerful waves crashing along the sand overnight.