‘The big one’ arrives, bringing behemoth breakers slamming into North Shore

Update 6:20 a.m. Dec. 23: The high surf warning has been extended to 6 p.m. Monday for the north- and west-facing shores of Kauaʻi and Niʻihau.

Original story: Meteorologist Drew Davis on Dec. 16 in an evening Instagram reel said the next incoming swell to sweep through the Hawaiian Islands would be “the big one.”

The Hawai‘i News Now weatherman’s words will now forever be part of Hawai‘i weather history as the first swell of the official 2024-25 winter season is bringing not just big waves to north shores from Ni‘ihau to Maui, but dangerously huge behemoth breakers.

A high surf warning is in effect for the north shores of Kaua‘i and Ni‘ihau until 6 a.m. Monday as surf — which was already pumping at 25 to 35 feet, well above warning levels — was forecast to rapidly build to massive heights of 40 to 50 feet by noon today.

The same warning is in effect for north shores of Mau, Moloka‘i and O‘ahu, where the The Eddie Aikau Big Wave Invitational surfing competition was green-lighted for today at Waimea Bay.

West shores of the same islands, minus Maui, are under the same warning, with surf of 15 to 25 feet already that rapidly built to 25 to 35 feet by noon today.

All North Shore beaches on Kaua‘i are closed until further notice because of extremely dangerous ocean conditions. Kauai‘i County Ocean Safety officials were already reporting waves of 30 to 40 feet before noon.

“Entering the water in these areas during the high surf warning is very hazardous and could cause serious injury or death,” said the Kaua‘i Fire Department in its closure announcement. “Beachgoers are also advised to use extreme caution, as large breaking waves are very dangerous for those standing along the shoreline.”

The public should not enter the water from Ka‘aka‘aniu Beach, also known as Larsen’s Beach, in Moloa‘a to Kē‘ē Beach and along Nā Pali Coast.

It’s serious and sound advice when an Alaska visitor went missing after she was swept into the ocean while swimming in waters off Hanakāpī‘ai on Nā Pali Coast and the U.S. Coast Guard rescued 5 people after their vessel capsized in waters outside Nāwiliwili Harbor.

Both incidents happened during a high surf advisory or while surf was still elevated following a recent swell along north and west shores of the Garden Isle, but nothing near the size of the monsters forecast today.

The Eddie has happened just 10 times in 40 years since it requires waves of at least 20 feet as measured “Hawaiian-style,” which is from the back of the wave, so wave faces can be twice that size.

“We are anticipating one of the biggest swells ever,” contest director Liam McNamara said Saturday on Facebook, according to an NBC News story Saturday.

The story further reports that Surfline forecasting director Kevin Wallis said a satellite measured one recent wave off a Hawai‘i shore at nearly 66 feet.

“That’s the largest satellite-verified wave height reading I can remember seeing in 25 years at Surfline,” said Wallis on the wave prediction service’s website.

The National Weather Service said satellite data estimated seas as high as 65 feet near a storm center well north of the state, with a nearby buoy measuring 60-foot waves.

The Kona and Kohala coasts on the Big Island’s west side also are under a high surf warning until 6 a.m. Monday, with surf of up to 12 feet expected to slam shores.

Breakers of up to 16 feet are forecast for north-facing shores of the island, resulting in them being under a high surf advisory until the same time.

Hawai‘i County closed several beaches because of high surf conditions, including Onekahakaha Beach Park, James Kealoha Beach Park, Leleiwi Beach Park (Wai‘uli), Richardson Ocean Park and Carlsmith Beach Park in Hilo and Kahalu‘u Beach Park and La‘aloa Bay Beach Park (also known as Magic Sands) in Kailua-Kona.

Additional beaches could close without notice.

National Weather Service observations by 4 a.m. today at offshore buoys northwest of Kaua‘i rapidly rose overnight as the largest in a series of extra-large overlapping northwest swells made its way toward the islands.

“Observations at the offshore buoys northwest of Kaua‘i show a 20-21 foot swell appearing to have leveled off this morning with the peak of this swell expected to reach the islands this afternoon,” said the weather agency’s 9:29 a.m. Sunday area forecast discussion for Hawai‘i.

The swell should gradually ease late tonight through Tuesday after reaching heights in excess of 40 foot faces along north shores with the highest exposure.

Surf heights could remain at or above warning levels well into Monday before falling to advisory levels sometime Tuesday.

This latest round of extended warning-level surf began Dec. 18.

Surf was already on the rise at the beginning of last week. Forecast models showed a long-period northwest swell would likely push wave heights along north and west shores of the state to above high surf advisory levels by midweek.

“The National Weather Service is already stating that this swell will likely exceed high surf warning levels Thursday into the weekend,” said Davis in his Instagram reel weather report.

Wave heights went above and beyond earlier than expected as the first in a series of large northwest to north-northwest swells arrived, building down the island chain by midweek.

The high surf warning now in effect for most of the state’s north shores — including Kaua‘i and Ni‘ihau — was first issued Dec. 18 and has been extended by the National Weather Service in Honolulu after the first in the series of extra-large overlapping swells arrived and was followed by another, causing wave heights to increase.

The high surf warning for Kona and Kohala shores on the Big Island was first a high surf advisory issued Dec. 19 that was upgraded to a high surf warning the evening of Dec. 20. The high surf advisory for north-facing shores of the Big Island was first issued early the morning of Dec. 20.

Both have also since been extended.

Giant waves such as those slamming into the North Shore of Kaua‘i and Ni‘ihau now will have significant impacts on the coasts.

Ocean water surging and sweeping across beaches, coastal benches and lava flows has the potential to cause considerable beach erosion along exposed shorelines and overwash onto vulnerable coastal roadways, properties and other infrastructure, especially during peak surf heights today.

Powerful longshore and rip currents also will be present at most beaches in the warning areas, and the monstrous breaking waves and strong currents could impact harbor entrances and channels, causing challenging vessel handling.

The National Weather Service said impacts will remain likely despite monthly tidal minimums, “underscoring the magnitude of this swell.”

Even just standing or being at the beach when a giant breaker strikes can be dangerous.

“Shorebreak waves can be a powerful and unpredictable hazard, especially in Hawai‘i,” said the Kaua‘i Lifeguard Association in an Instagram post. “When waves break directly onshore, the impact can knock people off their feet and drive them into sand, rocks or coral, risking serious injury to the head, neck and spine — even with waves as small as 3 feet.”

Waves travel a great distance without a continental shelf to slow them down before reaching Hawai‘i, so shorebreak in the islands is especially strong.

The nonprofit Kaua‘i Lifeguard Association, which is focused on maximizing ocean safety and has supported Kaua’i County lifeguards since 2003, advises to always check beach signs and speak with lifeguards about conditions — and stay back from the water’s edge.

Hawai‘i’s famous winter big surf is often caused by massive waves produced by Pacific storms that make their way to the state’s north and west shores, bringing powerful and unpredictable ocean conditions.

It is the deep low pressure and fierce winds of several powerful windstorms — some even as strong as a hurricane — moving across the Pacific well north of the islands, about 1,300 miles, generating the giant swells and huge waves spreading south and now bashing Hawai’i shores.

“We are also monitoring surf along leeward Big Island as the next pulse arrives on Thursday,” said the National Weather Service in Honolulu in a Dec. 18 Facebook post.

For up-to-date information about Kaua‘i ocean conditions and ocean safety, speak to a Kaua‘i County lifeguard at any lifeguard station, click here or call the Kaua‘i County Ocean Safety Bureau at 808-241-4984.

For updated information about ocean and weather alerts, visit the National Weather Service Honolulu forecast office website.