Wave of panic ... sea of calm

False tsunami alert leads to beach mayhem

A false tsunami warning caused havoc at a North Canterbury beach yesterday, forcing police to issue urgent messages to stop people fleeing in panic.

Whitebait fishermen at Kairaki Beach, near Kaiapoi, ran for their lives after seeing what appeared to be a wall of water heading towards them early yesterday afternoon.

Some remain adamant that it was more than an optical illusion cited by authorities as the most likely explanation.

North New Brighton fisherman Murray Brown was convinced a huge black line approaching the beach was a tidal wave.

"I swear to God I was watching a tsunami through my binoculars," he said.

Many of the 50 to 100 fishermen in the surf and at the nearby Waimakariri River mouth saw a similar threat, loaded their gear and "bolted"for fear of being engulfed by a massive wave.

Police, who had initially believed the tsunami alert was a hoax, changed their minds after several fishermen reported seeing the phenomenon, and the seaside settlement had probably its first traffic jam.

Senior Sergeant Tony Ellis, of the Kaiapoi police, and Civil Defence regional emergency management office manager Jon Mitchell said it was likely to be an optical illusion caused by reflections off the sea and clouds in calm conditions.

Brown said he saw waves breaking out to sea through his binoculars and the water was definitely stirred up.

"My heart was going 100 miles an hour. I was gone. There were people coming off the beach in trucks and trailers as the black line was getting wider," he said, sipping coffee to calm his nerves on the riverbank.

Brown said the strange formation appeared on the horizon for 45 minutes.

"It was coming closer all the time," he said.

"When I first looked, it looked like a line. The next time, it was getting closer and looked like a huge wave breaking out there."

Kaiapoi fisherman Anthony Powell said he had never seen anything like it in 25 years of fishing at the beach.

He and others were whitebaiting close to the Waimakariri mouth when they were alerted.

He had seen optical illusions there before in similar conditions, but these were "definitely waves", possibly caused by an undersea landslip.

"We were out in the surf whitebaiting and there were quite a lot of people on the beach. Then this guy drove up in a four-wheel-drive and was screaming out to us there's a tsunami coming," he said.

"Tell you what, everybody just panicked and got out of the water.

"A lot of us saw them, these breaking waves way out to sea. Then they calmed down.

"The waves weren't hitting shore. They were three to four to five miles out and they weren't coming right in. It was honestly quite frightening."

Mitchell said optical illusions could be convincing and it was easy for people to think they were seeing something that was not there.

If a tsunami was on the way from a distance, warnings would be on the radio, television and the internet, he said.

Ministry of Civil Defence and Emergency Management spokesman Vince Cholewa said there was no system yet invented that could warn of a tsunami that might be only minutes away.

"The big danger is if a big earthquake hits just off the coast. If you are on the coast and you feel a big quake and it is difficult to stand or you see the sea showing odd behaviour, then it is time to move," he said.

Yesterday's false alarm was encouraging in that it showed people were aware of the risk from a tsunami, he said.

QUICK FACTS

A tsunami is a series of waves created when a body of water, such as an ocean, is rapidly displaced. The Greek historian Thucydides was the first to relate tsunamis to submarine quakes. Some meteorological storm conditions can generate a storm surge which can be several metres above normal tide levels. A storm surge is not a tsunami.

- © Fairfax NZ News