HONOLULU (KHON2) — State officials said Oahu’s south shores will be seeing the biggest swell in decades this weekend.

While surf Friday rolled in at one to three feet range with occasional larger sets, the National Weather Service said by Sunday Oahu could see sets up to 20 feet tall — that’s almost as big as a two story building.

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Ocean Safety is urging everyone to be careful if you are heading to the south shore over the weekend.

Kurt Lager, Ocean Safety Acting Chief of Operations said people need to take this seriously.

“It’s not a time to just go and play,” Lager explained. “It’s gong to be a serious south swell with a lot of water moving.”

The NWS Honolulu Director of Operations Leigh Anne Eaton said the swell is historic.

“We are predicting this to be one of the largest swells that we have seen in decades, potentially comparing it to a swell that they saw back in the islands in 1995,” Eaton said.

Eaton said surf will start building Saturday peaking on Sunday with wave heights expected to be well into warning levels.

“Warning level is 15 feet. Right now we are predicting somewhere between 12 to 16 foot consistent (surf) with occasional 20 foot,” Eaton said. “This swell is from a distance source down in the southern hemisphere so it’s not related to (Tropical Storm) Darby at all.”

Other areas south of Hawaii already experienced the swell.

According to the NWS, a high surf advisory is in place until 6 a.m. on Monday, July 18.

The NWS stated that surf is expected to build up to 10 to 14 feet on Saturday, July 16 on south-facing shores throughout all Hawaiian Islands. On Saturday night occasional sets could rise to 20 feet all the way through Sunday night.

“In Samoa the other day, when the swell was passing through, they had a wave run up and debris on the airport runway. They had to close the runway. They had a lot of coastal inundation,” Eaton said. “And we saw that the swell almost doubled what some of the the wave models were predicting.”

Lager is urging beach goers and surfers to be extra cautious.

“The safest thing is high and dry,” Lager said.

That means when you are on the beach avoid walking on wet sand and wet rocks. If a wave breaks or washes up, it could pull you out.

Surfers should also beware.

“The surf’s going to be large enough there could be surges,” Lager explained. “With the south swells that generate down in the southern hemisphere, sometimes there’s long lulls between these big sets.”

Lager said they will have extra crew staffed along south and east shores patrolling on jet skis throughout the weekend.

These large swells may also impact harbors and boat handling.

The NWS recommends boaters be cautious of an increase in the number of surfers and bodyboarders utilizing the harbor channel access to surfing areas.

As the swell increases, the Hawaii Department of Land and Natural Resources is closing several State beach parks along the south shores.

Due to the conditions, the DLNR is also closing the following beaches on Saturday and tentative Sunday.

Hawaii Island

According to Hawaii County, these beaches will be closed until Monday due to debris brought in by the swell.

Puna

  • Isaac Hale Beach Park

Kau

  • Punaluu Beach (camping cancelled for the weekend)
  • Whittington Beach Park (camping cancelled for the weekend)

Kona

  • Milolii Beach Park
  • Hookena Beach Park (camping cancelled for the weekend)
  • Manini’owali Beach (Kua Bay)
  • Honaunau Boat Ramp
  • Kahaluu Beach Park
  • Laaloa Park (Magic Sands)
  • Pahoehoe Beach Park
  • Honl’s Beach
  • Hale Halawai Park
  • Old Kona Airport Beach Park

According to the National Park Service, Kaloko-Honokōhau and Pu’uhonua O Honaunau National Historical Park will be closed as well on Saturday, July 16 due to Tropical Storm Darby and high surf advisories.

Maui

  • Mākena State Park (open Saturday but may close on Sunday following conditions)

On Monday, July 18 the Maui Police Department will be participating in an Emergency Preparedness Training.

The training will take place at Molokai High School and intermediate school campus from 8 a.m. to 12 p.m.

Maui residents can expect to see emergency response vehicles, officers on campus and hear loud noises.

For safety, the MPD asks residents to avoid the training site.

Oahu

  • Makapu’u Tidepools
  • Keawa’ula Bay section of Ka’ena Point State Park may be subject to closure

The DLNR added that Kaiwi State Scenic Shoreline on the Makapu’u Point Lighthouse trail is an area of concern and is extremely hazardous during this time. Large swells are expected to peak during high tide in the late afternoon.

“We will be here at 9 in the morning,” Lager said. “We’ll have mobile response starting at 8 in the morning. We will stay as late as we need to be. We’re prepared to stay until everything’s taken care of.”

It’s important to heed lifeguard warnings.

Waikiki beach businesses, like Dive, Oahu & Surf, that normally rent surf boards and offer surf lessons plan to hold-off for safety reasons according to staff member Lonnie Steele.

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“So no surf board rentals, no boogie board rentals (on Waikiki Beach),” Steele said. “We will still rent umbrella and chairs though.”