(CNN) -- The biggest waves in a decade are forecast to be rolling toward Hawaii this week, but many surfers are set to miss out on the chance to ride them.

The National Weather Service in Hawaii said it expects waves 40-to-50-feet high to hit the north shore of Oahu on Wednesday, driven by "a giant northwest swell."

Hawaii hasn't experienced waves that large since 2004, said Sam Houston, a forecaster with the weather service.

A high-surf warning is in effect for much of the state until Friday morning and forecasters say "giant breaking surf," dangerous currents and significant "coastal inundation" are possible.

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At first glance, the tall waves would appear to offer a golden opportunity for participants in a big wave surf contest that was scheduled to take place Wednesday on Oahu.

But the organizers have postponed the event. They say that although the waves are expected to be pleasingly large, the wind conditions are no good.

The contest is held in honor of Eddie Aikau, a famous Oahu lifeguard who was regarded as one of the best big wave surfers of the 1960s and '70s. Aikau disappeared in 1978 during a canoe expedition from Hawaii to Tahiti.

Waves of up to 50 feet are sure to bring in towed-in surfers and spectators to Jaws, or Peahi, on Maui.

"It is a pretty awesome sight to see," said Anna Foust, emergency management officer on the island.

She said such waves from the northwest are generally not a threat to Maui's infrastructure. Still, she advised residents to be cautious of the high surf and stay well back.