He said the next thing he knew he was covered in debris and had lost his vision, unable to see right in front of his face.
"It just felt like someone kicked me in the chest. I was off the ground and spinning in circles."
Mr Heywood felt himself hit something and realised it was three horses that had been in the stable. He had no idea how they had got to where they were.
"My black truck was spinning doing 360s, there was no one in it. I closed my eyes and the next thing I was 200 foot [60 metres] away on top of one our horses."
He said calves and horses were also thrown around, with horses left shaking as if they were having a seizure.
Mr Heywood said he was so dizzy he started vomiting.
"I thought it was the end of the world," he said.
"The first thing I did was try and find everyone, I thought everyone was dead."
He said 37 children were at the back of the property on a horse trek, but luckily the tornado missed them.
The shocked children, believed to be from Mokoia Intermediate, and 13 adults were taken to the house to shelter with neighbours, while firefighters inspected the damage.
It was reported the school group was safe and well.
It was also reported Mokoia Intermediate principal Deborah Epp said when the mini tornado happened the children got off their horses and found shelter in a nearby building.
Mr Heywood said more than 300 trees had been uplifted on the property, hundreds of metres of fences destroyed and half a trampoline was stuck in the side of his house.
Once he knew all the people on the property were safe, his thoughts had turned to The Farmhouse's 72 horses and 406 calves.
"I don't know whether the animals are dead or alive."
Mr Heywood refused to go to hospital to be checked out because he said he could not leave until he could inspect the damage for himself.
"The path was narrow but the damage was wide. It was like a bloody bomb dropped," he said. "Someone was looking out for me."
The Rotorua tornado came after a storm had hit Auckland in which three people were killed and seven injured.
Sunnex Rd Resident Anne Bannan told The Daily Post the tornado "was sort of like something banging against the house. It was so loud and fierce".
She said power lines came down and were in water and the road was blocked.
A Tauranga Direct Rd resident said a tornado ripped through Hamurana, caused power outages, brought trees down and threw a trampoline across the state highway.
The man, who didn't want to be identified, said they were left without power from about 1.30pm until shortly before 5pm.