
There was supposed to be an open home at 81-year-old Alan Johnson's house on Sunday, but it had been torn to shreds during the storm that hit Mangawhai overnight.
"Top floor is gone, but every room is damaged," he said.
It was reported that a tornado hit the area during the wild weather.
Two people from Mangawhai were taken to hospital with serious injuries. One was airlifted to Auckland Hospital by helicopter and the other was taken to North Shore Hospital.
One of them was Johnson's daughter, who was at his Old Waipu Rd home at the time, and escaped by jumping down on top of the carport.
She is now in Auckland Hospital, awaiting surgery.
"She's got lacerations and broken bones," Johnson said.
Johnson said he was still in shock, but was relieved his daughter is okay.
Fire and Emergency New Zealand Northland manager Wipari Henwood said the initial estimate was 50 homes damaged, but he expected that number would go up due to homes and businesses in the wider area damaged by falling trees.
Johnson had worked for years to get his house ready to sell.
"It was supposed to be an open home today. It was an open home yesterday. The house was in beautiful condition, like tip-top condition. Now look at it.
"It is really devastating. We'd worked four years to get it up to this stage."

Meanwhile, Zoe Gimring said she woke to "the loudest roaring" and the sound of all of the outdoor furniture smashing against our deck railing.
"Across the road from us there's part of someone's roof through the neighbour's roof - luckily they weren't home."
Julie Wall's house had its roof torn off, and her family told her some of the debris ended up about 300 metres away.
Close to 5000 properties were without power in the Mangawhai, Mangawhai Heads and Langs Beach areas overnight. Power has since been restored to all except approximately 250 households on Moir St and Old Waipu Rd.
Power has been restored to thousands of households in Northland after a tornado knocked trees down and lifted roofs off houses.
Videos posted to social media showed several trees down across roads, with emergency services working to clear them.

Fire and Emergency New Zealand (Fenz) said shortly 5.30am they had received 16 calls from locals, starting about 3am.
It had sent "several" brigades into the area, where they found "roofs lifted from homes, fallen trees and downed powerlines".
The affected regions included Mangawhai and Langs Beach.
Most of the calls had been from people in the Molesworth Drive and Old Waipu Rd area, Fenz said, with a couple from Langs Beach and Ruakaka.
"Our initial response prioritised the calls that related to life safety. Firefighters extricated two patients and handed them into the care of St John," Henwood said.

A specialist drone team had also been called in.
It is not yet known how extensive the damage is, but one local reported that there were multiple houses on one street that had lost their roofs.
"People in the area should make safety their first priority and wait until daylight to assess damage to their property," said response coordinator Graeme Quensell.
"They should treat all power lines as live, and please avoid driving in the area so as not to hold up emergency services."