Firefighters and lifeguards yesterday kept surfers and swimmers from entering O'ahu's North Shore waters as big surf roared.

Warning signs were posted and beaches were taped off from Sunset Beach to Hale'iwa on O'ahu's North Shore. A high-surf warning remains in effect for all north- and west-facing shores of Ni'ihau, Kaua'i, O'ahu and Moloka'i; the north-facing shore of Maui; and the leeward coast of the Big Island through 4 p.m. today, according to the National Weather Service.

"It's still large and very dangerous," said Honolulu Fire Capt. James Mensching, of the Sunset Beach Fire Station. "Definitely no one should go in when the water is in conditions like this."

Firefighters teamed up with lifeguards to keep people out of the water for much of yesterday, Mensching said. The wave conditions caused the cancellation of the Quiksilver Big Wave Invitational In Memory of Eddie Aikau surf competition yesterday.

The unique one-day event can be held only on a day when wave-face heights are at least in the 30- to 40-foot range and ridable at Waimea Bay.

"The wind is onshore and breaks down the surfing quality," said lifeguard Capt. Bodo Van Der Leeden. "If the winds shift enough, the surfing quality will improve. Still, only expert surfers should enter the water."

The waves at Pipeline were estimated in the 18- to 25-foot range and traffic crawled along Kamehameha Highway because of the number of people turning out to see the waves. City lifeguards reported more than 1,200 preventive actions and one rescue on North Shore.

Lifeguards performed more than 800 preventive actions, 37 rescue craft assists and one rescue on the western side of the island, said Bryan Cheplic, spokesman for the Honolulu Emergency Services Department.

Honolulu firefighters rescued three kayakers who were stranded off Malaekahana, and a woman was taken out of the surf at Waimea Bay, said Van Der Leeden.

"It wasn't a good day to go out in a kayak," Van Der Leeden said. "Some people just don't know how to judge the ocean."

The O'ahu surf was expected to reach 25 to 35 feet last night on the north- and west-facing shores, said Sam Houston, a National Weather Service lead forecaster.

On Kaua'i yesterday, the Ocean Safety Bureau reported waves breaking on the north shore to be between 15 and 30 feet, said Mark McKamey, acting supervisor. Kaua'i lifeguards only recommended beachgoers go to Po'ipu and Lydgate beaches. All other beaches had dangerous surf.

A high-surf warning means dangerous, battering waves will affect shorelines, producing extremely hazardous swimming conditions and rip currents, Houston said.

No O'ahu roads were closed by the high surf, but there were reports of sand being washed onto Kamehameha Highway.

Waves continued to sweep over the road near the lifeguard office at Kawaena on the North Shore, said Van Der Leeden.

A small craft advisory also was issued for all coastal waters and channels, except for Ma'alaea Bay, according to the weather service.

Lifeguards recommend that beachgoers consult with a lifeguard before entering the water and heed all warning signs. People are also urged to go only to beaches with lifeguards, and never swim alone.

Reach Suzanne Roig at sroig@honoluluadvertiser.com.