"The guttering just couldn't handle it and it started flowing down and into the walls."
The amount of water was so strong it burst through ceiling panels as well as flowing down the inside walls "like a river".
While the main shop area was undamaged the water created pools in his accompanying office and a boardroom.
"There was nothing we could do," he said.
But what he did do was immediately call Unison, and the fire service, as the sheets of incoming water poured around the main power box, and lower power point sockets, and he was concerned it could start to electrically, dangerously arc.
He accordingly closed and evacuated the shop.
"The fire service were here very quickly — they cleared out the guttering and picked up the debris and put protective covers over everything as it was still coming in."
"We'd only had the guttering cleaned out last week," Kelly-Lowe said.
The power was also shut down and was expected to remain down through Wednesday, with staff hopeful of getting the doors open again on Thursday.
Electricians arrived first thing Wednesday to check through the system to ensure all was safe and well, and commercial cleaners were also on the job.
While stock had been undamaged he was concerned about damage to stored paperwork in the board room, and would be going through it over the next few days.
"I have never seen hail like that before — it was like being in Canada or the USA — you don't expect to see that here."
The building's owner, who also has other nearby properties, said while his other buildings had escaped damage he had heard reports of similar guttering-blocked incidents which had caused interior damage.
Carpet cleaning and drying crews had also been taking calls.