Updated 8:15 p.m.:

A huge northwest swell that hit the islands, peaking this afternoon, will continue Tuesday with very high surf, which will slowly subside.

The high surf warning will remain in effect until 6 p.m. Tuesday for north and west shores of Niihau, Kauai, Oahu and Molokai and Maui’s north shore.

A high surf advisory remains in effect until 6 p.m. Tuesday for the Big Island’s north and west shores.

The National Weather Service said a new swell will be building northwest of Hawaii through Wednesday. A front will arrive on Kauai’s shores by Friday morning, moving southeast of Hawaii island by Sunday morning.

The surf on north and west shores of Niihau and Kauai and north shores of Oahu, Molokai and Maui were expected to hit 30 to 40 feet tonight, and lowering to 20 to 30 feet Tuesday, the Weather Service said.

The surf was expected to be up to 20 to 30 feet tonight on Oahu and Molokai’s west shores.

Ocean Safety lifeguards performed a combined total of 102 rescues today on the north and west shores of Oahu.

They also took a total of 2,610 preventative actions by warning beachgoers on both shores.

Broken down, that is 68 rescues and 865 preventative warnings on the West Shore. And the North Shore had 34 rescues and 1,745 preventative actions.

Lifeguards on rescue watercraft continued their mobile patrol on the west side until 6 p.m.

The Honolulu Department of Emergency Management urging the public tonight to avoid Waimea Bay Beach Park because of the dangerous conditions from the extremely high surf.

Previous coverage:

With waves expected to reach between 35 to 45 feet on Oahu’s North Shore today, Honolulu Ocean Safety began patrols with two rescue watercraft at 8 a.m. this morning, and have opened lifeguard towers at Waimea Bay and Rock Piles, with extended hours.

Waimea Bay is staffed with three lifeguards and Rock Piles with two, according to Ocean Safety, which expects to extend its hours of operations in the area to around 6:30 p.m.

In West Oahu, meanwhile, the state has closed Yokohama Bay. Ocean Safety lifeguards are stationed at Yokohama Bay to inform potential beachgoers of the closure and the current hazards in the area, where surf is expected to be between 20 to 30 feet.

Ocean Safety will assess conditions around 3 p.m. today to determine if extended hours are necessary for the West Shore.

On Maui, Baldwin Beach Park in Wailuku will be closed Tuesday due to high surf and flooding, Maui County said.

Surf of 30 to 40 feet was expected today along shores of most neighbor islands as overlapping large northwest swells approached the state, the National Weather Service said.

A high surf warning was issued for north- and west-facing shores of Niihau, Kauai, Oahu and Molokai, and for north-facing shores of Maui. It is set to expire 6 p.m. Tuesday.

In addition, a high surf advisory has been issued for north- and west-facing shores of Hawaii island.

Surf was expected to peak at 30 to 40 feet today along north- and west-facing shores of Niihau and Kauai and north-facing shores of Oahu, Molokai and Maui before lowering to 20 to 30 feet Tuesday. Along west-facing shores of Oahu and Molokai, surf was expected to reach 20 to 30 feet today and begin dropping to 15 to 20 feet Tuesday.

The weather service said the combination of large surf and peak monthly tides could cause significant beach erosion and increase the potential for overwash along vulnerable coasts.

Residents and visitors should expect to see ocean water surging and sweeping across beaches along with powerful rip currents at most beaches, the weather service said.

On Sunday, surf was 8 to 15 feet in Hawaiian size, which measures a wave from its back, or about 15 to 30 feet when measured from the front, at Sunset Beach on Oahu’s North Shore, where surfers competed in the first round of the Vans World Cup of Surfing, said Jodi Wilmott, general manager of the Hawaii and Tahiti region for the World Surf League, which runs the event.

Wilmott said surf conditions were the best in nearly three decades for the event, with no wind, large swells, and clean and clear conditions.

Hawaii surfer Billy Kemper received a score of 10 during the round, the first perfect score in this year’s Vans Triple Crown of Surfing, which began with the Hawaiian Pro in Hale­iwa earlier this month.

Wilmott said the Vans World Cup event had a good turnout, but organizers were encouraging fans to watch the event on television because work on stabilizing the fragile dune system was continuing in the area. In December city crews removed a lifeguard storage shed at the beach that was teetering on the edge of a 20-foot drop because severe erosion had washed away part of the beach.

Wilmott said with the growing surf today, conditions were expected to be too washed out to hold Round 2 of the Vans World Cup, and instead organizers were focusing on the Jaws Challenge, which has been greenlighted for today on Maui.

Oahu lifeguards were also busy Sunday with 44 rescues and 1,900 preventive actions on the North Shore, said Dustin Malama, spokesman for the Honolulu Emergency Services Department.