HALE'IWA — Big waves usually mean big business for shop owners here.

But as swells reached 27 feet on the North Shore yesterday morning, DevOcean shop owner Marie Knoos said business was slower than usual.

And she understood why.

"In the morning when the waves hit, there wasn't a soul around. But it was because everyone was at the beach."

Knoos was among the many locals and tourists who welcomed one of the first winter swells of the season to the North Shore.

A high-surf warning continues for north- and west-facing shores through 9 a.m. today for all islands from Ni'ihau to Maui.

Victor Proton, lead forecaster for the National Weather Service's Honolulu office, said the waves are expected to hit 20 to 30 feet this morning on all north-facing shores, and 10 to 20 feet on all west-facing shores.

Yesterday, David Linson, a 56-year-old tourist from Lakewood, Calif., watched a handful of surfers and bodyboarders challenge the high surf at Waimea Bay.

"When you look at the size of the waves and compare them to the guys in the water, (the waves) look like they're 20 feet tall," Linson said. "I'm amazed they have the courage to get out there."

Linson's daughter Amanda, 21, said she surfs back home in California, but she would never get in the water to surf these swells.

"They come in and get really big," she said. "They're deceptive."

Waimea Bay lifeguard Johnny Angel said the strong rip currents can pose problems, even for highly experienced surfers and swimmers.

As a fellow lifeguard used a loudspeaker to bellow out instructions for a struggling bodyboarder yesterday afternoon, Angel said egos sometimes play a role in getting surfers and bodyboarders into trouble with the big waves.

"They know the whole beach is standing up and watching them," Angel said. "We make an example of them because people don't want to be heckled that bad."

Reach Leila Wai at lwai@honoluluadvertiser.com.