Sonic BOOM

LIHUE — Military fighter jet training is routine north of Kauai, but it’s unusual for it to rattle windows and shake houses like it did Thursday morning.

Residents on the Eastside and North Shore reported loud booms about 10 a.m. Some people heard the booms, others felt the vibrations.

“We felt it more than heard it in the Wailua Homesteads,” said resident Lori Stitt. “I felt a rumbling from the back part of our house. It backs up to a hill. Our whole house was rumbling.”

She continued: “It reminded me of a California earthquake, however it didn’t seem like the ground underneath where we were was moving. Only part of our house was rumbling.”

On social media, theories ranged from falling trees and earthquakes, to trouble with North Korea.

“Rocked my world in Anahola! What was it??,” one social media post reads.

“Ok, Kauai what the heck was that deep boom a fee (few) minutes ok, seemed to have come from the mountains, windows shook for 10 seconds? This was in the Wailua Homesteads area,” another post says.

Other social media posts reported windows shaking in Kapahi and Keapana. One person said they thought it “sounded like a bomb.”

“Loud boom, followed by shake, followed by the neighborhood dogs going off. What was that Kauai?” another resident posted online.

In reality, it was Hawaii Air National Guard that caused a rogue sonic boom during its first large-scale “Sentry Aloha” fighter exercise of 2018, an exercise that started Wednesday and continues through Jan. 24.

A notification wasn’t sent out to Kauai prior to the event, because training of this kind is something that occurs often according to Lieutenant Colonel Charles Anthony, director of public affairs for the Hawaii Air National Guard.

“We don’t ordinarily put out news releases every single time we conduct aerial training or host a Sentry Aloha like this, but in retrospect maybe we should have,” Anthony said. “We didn’t mean to alarm anyone.”

Hawaii Air National Guard flies F-22 Raptors in a training airspace north of Kauai six days a week and the only time a news release is usually generated is when kona winds could affect noise levels on Oahu.

“Having fighter aircraft go supersonic happens all the time, but what is rare is when a sonic boom carries far enough that it actually can be heard or felt on Kauai,” Anthony said. “But, sometimes you can get windows rattling and that sort of thing.”

Cloud cover and wind direction are two factors that could have helped carry the sonic boom far enough that it was felt and heard on Kauai, he said.

“It can travel quite a long distance depending upon what the weather conditions are like,” Anthony said. “Typically there’s no impact on the island of Kauai, this happens to be one of those exceptional times.”

Residents said notification of these kinds of exercises would be helpful, since many didn’t know what was causing the loud booms Thursday morning.

“I think that a broad announcement of military exercise isn’t enough for residents, we need to know what to expect, (like) ‘ranging from loud bomb-like sounds to rattling houses to feel safe,’” Stitt said.

Anthony said though the training exercises are ongoing through Jan 24, residents might not hear another sonic boom in relation to the training. Then again, they might.

“Typically no one would even know this fighter activity is going on. Today is the exception,” he said.