SYDNEY (REUTERS) - Mr Branko Sugar and his son were spearfishing on an outer reef in Tonga last Saturday (Jan 15).
The air smelt of sulphur, as it had done for weeks, from the nearby active volcano, but he noticed the ash cloud from the crater was much higher.
As the 61-year-old stowed away his spearfishing gear, the first of four loud volcanic explosions rocked the tranquil South Pacific, sending a giant wave towards his boat.
"We stopped the boat and just looked. Then we saw the wave coming towards us. The biggest wave I've ever seen," Mr Sugar told Reuters via telephone from Tonga on Friday where communications are still only being restored.
Mr Sugar turned his boat, a 400-horsepower 27-foot (8m) World Cat catamaran, and accelerated towards deep water near Eueiki Island.
"That's what saved us, the power of the boat," he said. "I shouldn't be alive."
As he raced for safety, Mr Sugar telephoned his home on Tonga's main island Tongatapu to warn of the approaching tsunami, but nobody answered.
"The wave came past us and hit the main island, and then we knew we'd managed to get away. But then the rocks started raining. It was raining stones," he recalled.
In minutes, the Pacific blue sky turned to total darkness, ash enveloped everything and a storm seemed to whip up, lashing the boat with wind and waves.
A 12-mile (19km) trip home took three hours in the darkness before they reached the harbour.
"There were wrecked boats everywhere. Upside-down boats, sunken boats. We didn't know where to go," Mr Sugar said.
"And when we finally stopped, then we couldn't find our cars - they'd all been swept away. It was one thing after another. When we finally found them, I couldn't drive, I was blind from rocks pounding my eyes for hours driving the boat."
The Hunga Tonga-Hunga Ha'apai volcano eruption triggered tsunami that destroyed villages, resorts and many buildings and knocked out communications for the nation of about 105,000 people. It also sent shockwaves and tsunami across the Pacific.
Three people have been reported killed, say Tongan authorities.
Nasa's Goddard Space Flight Centre has said the force of the eruption was estimated to be the equivalent of five to 10 megatons of TNT, or more than 500 times that of the nuclear bomb the United States dropped on the Japanese city of Hiroshima at the end of World War II.