Big surf will hang around today, with advisory levels likely continuing for east-facing shores but ending for the north shores of the main Hawaiian Islands, the National Weather Service predicts.

Haena on Kauai’s North Shore came out on top with monster waves of up to 25 feet Monday.

Beachgoers to the east shores might see 8-foot surf today, enough to trigger warnings for those areas, while north shores could see a drop below advisory levels to 12 feet, down from 15 feet.

"This is the most challenging swell" to predict thus far this season, said National Weather Service lead forecaster Sam Houston. The buoy numbers are one to two feet higher than the predictions by wave models, he said.

"We will watch buoys overnight," he said.

The weather service also cautions that an advisory means high surf will affect beaches and produce large breaking waves and dangerous rip currents.

The swell brought 12- to 15-foot surf to the North Shore, where the HIC Pro surf meet was under way Monday at Sunset Beach.

Oahu lifeguards issued 770 warnings to North Shore beachgoers and 275 warnings to those on the west side. There were 10 watercraft-assisted rescues at Laniakea on the North Shore and one on the Wai­anae Coast.

"The way the swell is hitting from the north, Lani’s really gets it," said Shayne Enright, spokes­woman for the Emergency Services Department.

"Our lifeguards are doing a very good job and working extremely hard to keep the public safe," she said. "We just ask beachgoers to listen to their warnings and advisories, and if they ask them to stay out of the water, please do so."

Waves measured 15 to 20 feet at Maui’s Hoo­kipa Beach and 15 to 20 feet at Baldwin.

Richardson’s on the Hilo side got up to 8 feet.

A surfer in his 40s was taken in critical condition to the hospital Sunday afternoon after city lifeguards pulled him out of the water at Sandy Beach.

A snorkeler noticed a surfer in trouble near the surf spot Full Point at 4 p.m. and notified lifeguards.

Lifeguards on a paddleboard pulled the surfer out of the water and performed CPR until paramedics arrived and took over treatment.