Experts: A Cat 4 hurricane would leave Honolulu’s airport under 9 feet of water

HONOLULU (HawaiiNewsNow) - When you look at Urban Honolulu, it’s hard to imagine what it would look like if a major hurricane were to make a direct hit.

But scientists and emergency management officials have been doing more than just imagining it.

And they have a good idea of just how bad it would be.

Iniki was a Category 4 hurricane with 145 mph winds when it made its direct hit on Kauai in 1992, destroying or damaging more than 6,000 homes.

“If the same system hit Oahu, that would be really a disaster because here property values are so high,” said state climatologist Pao-Shin Chu.

SPECIAL SECTION: HNN Hurricane Center

One of the biggest threats would be flooding in a major urban area.

“Here in Hawaii, our development is concentrated along the shoreline for the most part and our low-lying areas that are already flood-prone. So sea level rise is only acting to compound those risks,” said Brad Romine, a coastal geologist and coastal management specialist with the UH Sea Grant College program.

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How bad would the flooding be?

NOAA’s hurricane surge maps show many areas of Downtown Honolulu and Waikiki would be under 3 to 6 feet of storm surge if a hurricane of Iniki’s intensity made landfall from the south.

Parts of Daniel K. Inouye International Airport would be more than 9 feet underwater.

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Of course, there’s also the wind threat.

Experts said what happened on Kauai would be multiplied on Oahu because the population is much more dense.

“We have a significant amount of homes that are built to older design standards that are not equipped or haven’t been retrofitted to withstand wind,” said Jennifer Walter, deputy director of the Honolulu Emergency Management Agency. “And that has a lot of implications, both for the immediate response and the long-term recovery.”

In recent memory, Oahu’s closest run-in with a hurricane came in 2020, when Hurricane Douglas passed just 30 miles north of Kahuku as a Category 1 storm.

Hurricane Preparedness Resources:

― Hurricane evacuation information for residents across Hawaii

― Preparing your home for a hurricane should happen before the storm nears

― Here’s what to do before, during and after a hurricane hits

― Here’s everything you should have in your emergency hurricane supply kit

The island was spared from the strong winds and heavy rain that were on the northern half of the tropical cyclone.

But if it had passed 30 miles to the south of Honolulu, much of downtown and Waikiki would be covered by up to 3 feet of ocean water and heavy rain runoff.

“It would have had a significant impact from storm surge, presumably rainfall flooding, but also large waves that would have come from the storm passing south of us as well,” Romine said.

After the storm passes, emergency officials said power will be lost, cell towers may come down, and the internet may be spotty, if it works at all.

“Think about what that means,” Walter said. “Whose phone number do you need? Where do you need directions to? I’m someone who’s completely dependent on Google Maps. Do you know how to get to where to go?”

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