Throughout the morning today, visitors were arriving in increasing numbers on O'ahu's North Shore to see what forecasters say will be the biggest waves of the season along the famed seven-mile surfing mecca.

Wave heights are expected to reach 35 feet today.

Under clear, sunny skies, today's morning waves were barely reaching the 7-foot mark at Sunset Beach, one of the few North Shore locations that had rideable waves at all.

But even then the drama was building. Leonard Brady of Los Angeles came off a 6-foot wave at Sunset and spoke of the magnitude of what was happening.

"You can feel the energy," said Brady, 59, a former Hawai'i editor for Surfer Magazine, as he pointed to white water rarely seen so close to shore. "There's too much current and too much white water for how small the wave is. That's real energy that's coming in from that deep storm that's pushing in."

That was around 11:30 a.m. Soon, Brady predicted, the waves would be too much for the average surfer to handle. He described the brief moment as a rare window of opportunity for ordinary surfers to be part of one of the mammoth wave systems that have made the North Shore famous.

Moments earlier, Brian Dunlap, 18, of Lakewood, Wash., had learned that lesson the hard way. Having never surfed before, and enjoying a Hawai'i visit before heading off to Marine boot camp in San Diego, he paddled into the Sunset Beach waters on a $2, used boogie board he bought at Goodwill.

After making an attempt at riding a 6-foot wave, Dunlap discovered he was unable to paddle back to shore because of strong currents.

Watching from the beach, his dad, retired Army Sgt. Richard Dunlap, began to worry. The elder Dunlap, figuring Brady looked like someone who knew what he was talking about, asked the experienced surfer what to do.

"I was getting a little worried because this was our first time doing this," said Dunlap after his son had safely returned to shore. "He told me my son was doing the right thing by just letting the current bring him around to the east and on back into shore.

"But he said if he was any more to the left, where the reef is, that that's one of the most dangerous rip currents in the world."

"I did feel the energy," exclaimed Brian after his big wave adventure — holding up what was left of his board, which had broken in half. "And it was exciting."

A high-surf warning remains in effect for north- and west-facing shores of Ni'ihau, Kaua'i, O'ahu, Moloka'i and Maui, the National Weather Service said.

Surf along those shores is expected to reach 25 to 35 feet today, forecasters said.

The high-surf warning is also in effect for west-facing shores on the Big Island, and a high-surf advisory has been posted for the west-facing shores of Lana'i and north-facing shores of the Big Island.

The surf will build rapidly along the affected shorelines from Ni'ihau to Maui today and along the west-facing shores of the Big Island this evening, the Weather Service said.

The high surf, which was generated by a storm to the northwest of the state, is expected to continue into the weekend.