"We heard the hailstones and I walked around the corner. I was looking at the ceiling in our wheelchair bay. The water was just dripping through and then the patient call bells went off, and we tried to turn them off.
"As I was putting tape on, my co-worker just said, 'oh my gosh, quick move' and as I looked up it just gushed down like a waterfall. Then the ceiling came down and it just missed both of us."
Miss Kay said it was a close call.
"A piece of the ceiling had just opened up and that's the one that came down and that's the one that just about hit me. But, as she yelled out, I looked up and pushed myself back and got wet, but luckily missed it."
All 12 patients in the Mangorei Rd hospital remained safely in their beds throughout the ordeal, she said.
Fire crews came to the hospital and assessed the building after the ceiling collapse.
She said they were given the all-clear and there was no need for a late night evacuation.
The roof had remained intact but the ceiling was exposed and there had been extensive water damage.
"There's just water everywhere and also bits of jib and chalk all over the floor," she said.
Miss Kay and her colleague had been mopping up through the night but the clean-up and repairs would continue today.
Meanwhile, firefighters in Christchurch and Banks Peninsula were kept busy with 19 wind-related call-outs as gales pounded the Canterbury region last night.
Southern Fire Service shift manager Brent Dunn said power lines and trees were levelled by the strong winds which created havoc until easing just after midnight.
He said firefighters were also called out to secure roofs lifting on houses and a trampoline that had blown into the side of a house in Lyttelton.
While the winds died after midnight a strong wind warning remained in place. All other severe weather warnings for the rest of the South Island had now been lifted.
Travellers were being warned to take extra care on two state highways where slips and storm damage had reduce roads down to one lane.
Sections of the Haast and Lindis Pass were affected and motorists were being warned to take extra care as crews repaired and cleaned up blocked roads.
Work was expected to take several days with minor slips continuing.