Dangerous surf of up to 35 feet is expected on north shores of Oahu, Kauai, Niihau, Maui and Molokai this afternoon into Friday.

The National Weather Service has issued a high surf warning that also includes west shores of Kauai, Oahu and Molokai.

"Surf will build rapidly today, reaching warning levels on Kauai and Oahu by afternoon and Maui County in the early evening hours. Large hazardous surf will hold through Friday afternoon and then diminish," forecasters said.

The warning is in effect until 6 p.m. Friday, but advisory level surf is expected to continue until Sunday, dropping to advisory levels briefly Friday evening, when another swell arrives pushing surf up to dangerous levels again.

Surf is expected to be in the 10- to 15-foot range through this morning and build to 25- to 35-foot heights by this afternoon and evening on north shores.

West-facing beaches will see 8- to 12-foot surf this morning building to 15- to 25-feet this afternoon and evening.

"This is may be one of our largest and most dangerous periods of high surf this season", said Melvin Kaku, director for the Honolulu Department of Emergency Management.  "We can expect sand and seawater incursion on roads and highways, and onto private property. We are also concerned that our homeless families living along affected coastlines could be at risk.  We will be notifying service providers as well as tasking our Reserve Corps Volunteers to warn the homeless along those shorelines." 

The most significant hazard to North Shore coastal areas can be expected to coincide with the high tide occurring on Friday morning at 4 a.m. Residents living in homes along or near the shoreline should be prepared to evacuate immediately if their homes are threatened, city officials said. 

"These dangerous conditions mean that only highly experienced persons should enter the water. Inexperienced persons should remain off beaches and adjacent beachfront areas. Large breaking surf, significant shore break and dangerous currents make entering the water very hazardous. Anyone entering the water could face significant injury or death," the National Weather Service said.

A spokeswoman for the Quicksilver in Memory of Eddie Aikau big wave surfing competition said organizers are monitoring the two approaching swells to see if the contest, which is only held when waves are about 35 feet or higher, and consistent enough, at Waimea Bay, can be held.

She said, at this point, it looks like the waves may not be consistent enough to meet "Eddie" standards on Friday. But they are still looking at the swell that is expected to arrive Sunday.

The last time the contest was held was in 2009.