A 9-year-old boy died after he was knocked down by large waves and swept out to sea while playing in the surf with his father at a beach in California on Tuesday.Waves breaking between 8 to 12 feet were pounding Monastery Beach in Carmel when the boy was swept out at 12:43 p.m. The father was able to grab onto his son for a moment before they were separated by big waves.The boy's father wanted to go into the surf after his son, but onlookers prevented him from entering the water, CalFire captain John Spooner said. The father was not a strong enough swimmer to make it to his son."He tries to go back in, and the bystanders, seeing that he wasn't going to be able go in successfully based on size of surf and conditions, prevented him from going back into the water," state parks ranger Sean James said. The boy struggled in the water for 20 minutes until a rescue team from Pebble Beach pulled him out of the water onto a boat. They performed CPR on the boy, and he was rushed to a hospital where he died. Monastery Beach is also called "Mortuary Beach" by locals because so many people have drowned there. The boy and his family live in Alhambra, Calif., in Los Angeles County, and were visiting the Central Coast. His mother was also at the beach. State parks officials say it's the steepness of Monastery Beach that makes it dangerous. "What makes this particularly dangerous is the contour," State Parks Monterey District superintendent Jim Bilz told KSBW in a past interview. "It's probably 30 feet that it very sharply goes down at an angle. The contour is created by the deep shelf off the coast here."In February of 2015, 57-year-old Linda June was walking with her family on the sand when a wave dragged her into the ocean and she drowned. June was a tourist from Illinois.Surfline.com is forecasting that the surf along Monterey and Santa Cruz beaches will be even higher next week, with 13-foot waves expected on April 4, 7, and 8.