The first major swell of the winter surf season made a dramatic debut along the North Shore on Monday, resulting in two hospitalizations, hundreds of preventive actions by ocean safety personnel and the early closure of Waimea Bay Beach Park.
According to Department of Emergency Services spokeswoman Shayne Enright, conditions at Waimea Bay were "extremely dangerous," with a 10-foot shorebreak and long intervals between sets.
"The thing that concerns us is that the water can look totally flat for 30 minutes at a time and then in just a few minutes start taking out people," Enright said.
Paramedics treated a 23-year-old woman who was seriously injured in the surf. She was transported to an area hospital at 11:45 a.m. A 14-year-old boy, also injured in the surf, was taken to the hospital in stable condition at about 1 p.m.
Two other beachgoers suffered shoulder injuries and were treated but did not require hospitalization.
In all, lifeguards took an estimated 500 preventive actions and provided direct assistance to 25 other people.
The Department of Parks and Recreation closed Waimea Bay Beach Park at 6 p.m.
Enright said Ocean Safety personnel would reassess the area early this morning.
Lifeguards taped off the Sharks Cove and Three Tables areas to beachgoers earlier in the day as a precaution.
Surf conditions are expected to intensify over the next day or so.
The National Weather Service reported that a northwest swell was generating surf between 12 and 20 feet high along north-facing shores of all islands and 10 to 15 feet high along west-facing shores Monday. Waves are expected to reach heights of 25 feet on north shores and 20 feet during the peak of the swell Tuesday night and Wednesday.
A high-surf advisory is in effect for the north- and west-facing shores of all islands until noon today, when it will become a high-surf warning effective through 6 p.m. Wednesday, according to the weather service.
A small-craft advisory has also been issued until 6 a.m. today.
The weather service predicts the surf will gradually decline after Wednesday but remain elevated through Friday.