Life Pharmacy Rotorua owner Brett Fordyce could only stand and stare as his Central Mall store became submerged by a waterfall that poured in through the ceiling and washed out the back door.
Fordyce had gone to the store on Sunday morning and discovered a couple of ceiling tiles had fallen down and there was a little bit of water on the floor.
"I thought 'I can work with that' and started cleaning before we opened the doors," he said.
"But within minutes more ceiling tiles started peeling off the roof and then the deluge of water happened."
He said it rushed in through the top and flowed out the back "like a river".
"I turned the lights off as they had started to spark but, aside from that, there wasn't really much else to be done other than watch."
From what he understood, water had leaked into the ceiling cavity of the mall.
"Once there it had soaked the porous ceiling tiles which had eventually become too heavy and dropped.
"It was quite spectacular watching it all happen."
Fordyce described the store as a disaster.
"We have managed to open the dispensary today but I'd say the clean-up is going to take at least a week."
He said a high percentage of the store's stock was damaged and would have to be dumped, the shelves all needed checking and then staff would have to restock.
"At the end of the day, what's done is done. You can't really say too much more or lay blame for what was a natural event."