The deluge of rain that fell in West Otago on January 16 and 17, 1980, forced the river over its banks, sending a volume of water almost 3m deep coursing through the town.
This was Kelso's second major flood in 15 months.
The town succumbed to the "100-year-flood" of October 1978, from which it had just recovered when the 1980 flood struck.
Ken Thomson (75), of Tapanui, was born and bred in Kelso.
He said right from the time he went to school, he could remember the town flooding.
"You could just about count on it every year - but nothing like the extent of the last two floods."
He was on holiday in Christchurch when the 1978 flood warning was given.
At 7.30pm, Mr Thomson tried to use the motel reception telephone to call for an update.
"The phone exchange had been blown away about 7pm, so we knew then it was pretty bad."
Mr Thomson made the decision to travel back to Kelso, but only made it as far as Milton, where the road had been closed.
At the flood's height, Mr Thomson said water almost 2m deep was flowing through his house.
"I got into town the next morning - and drove right up to my back door. All the water was gone. There was no water in the house."
Even though things did not look dramatically different, Mr Thomson said he "knew there had been a flood".
He planned to build a new house away from the flood plain, and was living in a farm cottage when the 1980 flood waters began to rise.
"The section I bought - on the Terrace - didn't have any water on it during the flood. That was before the 1980 flood, but they stopped all building there after that."
The magnitude of water that flowed though Kelso during the 1980 flood was larger than that of the "100-year-flood" in 1978, and the devastation proved too great for the town to recover.
Any further building in Kelso was prohibited by the government and local catchment boards, ending what hope there had been for the town's survival.
During the 1960s and 1970s, Kelso is thought to have had a population of about 200.
It boasted a three-teacher primary school, a service station garage, shops, hotels and a rail yard.
Mr Thomson said the rail line closed after 1978, and estimates the population was about 80 people when the 1980 flood occurred.
The town's biggest shop, the Kelso branch of Wrightson NMA, closed after the 1980 flood, along with the school.
The houses that could be salvaged were moved to other towns, and everything else was demolished, Mr Thomson said.
Thirty years on, there is not much left of Kelso - just the derelict remains of the old dairy factory, sitting lopsided in a grassy paddock, and some concrete guttering on the side of the road where the Wrightson NMA building used to be.
But the memory, and the enduring spirit of Kelso, survive in the hearts and minds of the people who once lived there.
