Pacific Tsunami Warning Center Miscalculated Wave Impact on Hawaii Shores

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Tsunami wave (Photo courtesy of NOAA)

BY MALIA ZIMMERMAN – On Saturday evening, people across the state were enjoying early Halloween events and street festivals, dinner parties with friends and family, movies, and even a wedding, when they heard an announcement at 5:04 p.m. from the Pacific Tsunami Warning Center: A 7.1 earthquake had hit the Queen Charlotte Islands in British Columbia, Canada, but no tsunami was generated and no action was needed.

A couple of hours later, the story changed. Residents and visitors learned the earthquake was actually a 7.7, higher than the Alaskan Tsunami Warning Center’s initial said, and they were ordered to evacuate from shorelines and flood zones, because a tsunami was scheduled to hit Hawaii at 10:28 p.m.


This was the third time in three years Hawaii residents had to prepare for a tsunami – and by now, most knew the drill.

But there was still a great deal of confusion among some residents because earlier they were told there was no tsunami, and suddenly the state was in tsunami warning status, with just two and a half hours notice that a tsunami was imminent.

First responders began mandatory evacuations from beaches, all shorelines and flood zones.

On Oahu and the Big Island, sirens that are supposed to sound warnings in times of emergency and are tested monthly, worked in some places and not others.

Fire fighters took their fire trucks and bullhorns and drove through neighborhoods to make sure those in flood zones left their homes. Boat owners went to the docks to tie up their boats and then raced out of the flood zones as soon as they could. Drivers across the state raced to the gas stations, fearing that if the electricity went out, they would not be able to get fuel. Others packed the grocery stores, buying Hawaii emergency staples: Water, toilet paper, batteries and rice. Darkness, and heavy rain showers, added to the confusion for some, who could not get a read on the ocean’s temperament.

Being on an island, mandatory evacuations send a great many people scrambling for higher ground, including visitors in Waikiki who are told to evacuate vertically by going to higher floors in their hotels.

Roads closed at 9 p.m. and while some chose to ignore the warning, most people prepared for what might hit.

Pacific Tsunami Warning Center on Oahu (courtesy of NOAA)

At 10:28 p.m., tsunami waves did begin to hit Hawaii every 10 to 12 minutes, but fortunately, they were just about 1.5 feet high. On Maui, waves reached as high as 4.5 feet in Kahului. The counties of Maui, Hawaii Island, Kauai and Oahu reported either little or no damage from the tsunami waves, but there were four serious car accidents on Oahu, and on Molokai, there was some damage to property near the ocean.

But what happened between 5:04 p.m. and 7:15 p.m. to bring the state straight into a warning status and was it necessary?

Gerard Fryer, a senior geophysicist with the Pacific Tsunami Warning Center, the federal agency responsible for tracking tsunamis, admits the warning probably was not necessary. He said they most likely should have issued an advisory to keep people out of the water and off the beach.

He said the tsunami was 100 miles long and 20 miles wide, and scientists at first were looking at the wrong angle. While the shorter waves were hitting the West Coast, longer, much larger waves were headed toward Hawaii shores, aiming right at Oahu, Molokai and Maui.

When they realized their error, they issued the warning. But the scientists tried to fit the tsunami in a model that did not work, and they did not realize the waves would disperse so much by the time they arrive in the islands three hours later.

“We automatically assumed the worst case,” Fryer said, adding they “were not smart enough to take account” of the water spreading out as it traveled across the ocean, reducing the size of the waves as it progressed.

“I suspect we probably overestimated the wave by a factor of 2,” he said, which is 5 feet vs. 2 feet. “Five feet is big enough to cause flooding, and 2 feet is not. We had forgotten about the dispersion, and that cut down the altitude down,” Fryer said.

They made “scientific blunders,” he said, adding, “I am afraid poor Hawaii suffered for it.” Fryer said that with each tsunami event, the geophysicists charged with tracking the tsunamis learn valuable lessons.

“We won’t make this same again,” Fryer said, joking “We will not shoot ourselves in the other foot.”

Fryer said most people in Hawaii are understanding and cooperative, particularly because they’ve seen the devastation from tsunamis as recently as the Japan tsunami in March of last year.

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  1. Well, the poor guy whose Jeep was hit by a drunk driver in Waialua would likely not have been parked by the side of the road had these geophysicists been more accurate. So the mistake is funny, but not really.

    Also, I know I don't have a Ph.D, but wouldn't a simple bathtub experiment have told you that the force produced by an initial shock at one end of the bathtub would be significantly less impactful at the other end of the bathtub?

  2. Yes there were four major accidents that night, and a lot of other consequences including a cancelled school fundraiser and a rushed wedding. Would be good if they had the tools to get the assessment right, especially if they cost less money.

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