A father and his two children were swept into the ocean on Saturday at Falcon Cove.
Falcon Cove is located near Arch Cape, north of Oswald West State Park.
The father was holding his children, a 7-year-old girl and a 4-year-old boy, when they were hit by a large wave that pulled them into the water.
When police arrive, the father was struggling to get out of the water and the girl was farther out in the surf. A police officer pulled her out of the water.
The Coast Guard searched until 6 p.m., but wasn't able to find the boy. They were limited to searching by helicopter, because the Ocean Bar is closed, due to high waves.
The girl later died at a hospital.
The waves were especially high this weekend, because of a combination of a King Tide and storms.
A King Tide occurs when the Earth, Moon and Sun are in alignment.
Officials are warning people to stay off beaches, jetties and rocks during this time, because of the risk large waves might unexpectedly come ashore.