Everything changed in mere minutes - although Mrs Williams said it seemed like forever.
"I knew what it was - I realised it was an earthquake," she said.
Her mother had told her about earthquakes, having been through some major ones when she lived up Tarawera way.
"She told us how they made trees sway and move but I thought no, that's probably just a story."
On February 3, 1931, she suddenly knew her mother's tales were not made-up stories.
The floor of the building began to roll and she could hear things crashing down and people calling out in fear.
She and her workmates got into a huddle until the shaking fell away and then made their way outside.
The landscape was one of dust and rubble.
Cars were covered in broken masonry and bricks.
"I was just numb - I was in shock," she said.
"I saw people injured and I knew some of them."
Her thoughts slowly began to focus and they focused on getting home - and of her mother, a sister and two brothers - her father had died when she was a child and her mother was bringing up the three alone.
Her sister had been at the Technical College which was destroyed by the earthquake, claiming many young lives.
"I knew some who died and that was very tough to take in."
One of her brothers had been at their home in Sales St and the other had been out working for a grocery business.
Before she was able to get home and discover they had all come through unscathed, she was told to head for the hill, as there could be a tidal wave coming.
To the relief of everyone's already shattered nerves, it did not arrive.
"The house came through all right - only the chimney had come down," she said.
As fire raged uncontrolled in the central business area and water and gas supplies were damaged and erratic, they were sent to Nelson Park where tents and shelters had been set up.
The aftershocks continued for days and it was decided she, her mother and her grandmother should evacuate to Palmerston North to stay with relatives, although the overcrowded house saw them eventually take up temporary residence at the Palmerston North Showgrounds - more camping.
"We came back after two or three weeks and moved back into the house," Mrs Williams said.
The gas had been replaced by electricity and life slowly started to move on again.
"There were plenty of aftershocks but I just got used to them," she said.
She remembers the Mardi Gras returning to Marine Parade and the dances sparking up again.
Life started getting back to normal.
"When I feel an earthquake now it doesn't bother me too much."
She said she felt for the people of Christchurch and knew well what they had gone through, and what they faced.
"But it's progressing so slowly there - after two years we were all organised."
At 102 she is the oldest known earthquake survivor and on Sunday she will join other guests at the annual Earthquake Survivors gathering at the Napier Boys' High School hall.
There will be music from that era as well as a display of historic photographs, and of course tea and cake.
The honour of cutting the cake will likely go Mrs Williams' way again.
"I've been cutting it for the last three or four years," she said with a smile.
"And it's good to pick up with the younger ones again because there aren't too many my age."
The younger ones are the guests in their 90s.
