Mr Christiansen, general manager of the Golden Gate Lodge and a Cromwell Community Board member, was having dinner with his wife Sarah and their three young children about 6.15pm on Friday when their house was hit by what they describe as a tornado or whirlwind.
As they watched the "swirling wind" approach, their home's ranchslider was blown out of its frame by the force. Mr Christiansen tried to hold it in place, while the rest of his family took refuge in the laundry.
Once the whirlwind had passed, they discovered the damaged door was the least of their worries. Outside, their 6m, twin-axle caravan - which Mr Christiansen and his son Baxter (3) had been in just half an hour earlier - had been lifted into the air, flipped up and over their aluminium dinghy, and landed on its roof.
Their trampoline, which had been tethered in their backyard, had been ripped from its moorings and blown on to the nearby golf course.
Witnesses from the petrol station across the road rushed over to check on the family. Among them was Dunedin broker Peter Young, in Central Otago on a golf trip.
"I noticed near the Big Fruit there was a big dust storm twirling round," Mr Young said.
"When he glanced back a few moments later he saw "a trampoline flying through the air".
It was carried 30m, about 3m metres off the ground, before hitting the ground and rolling at high speed for another 200m into trees on the golf course. He then saw the caravan lift 3m into the air before overturning and dropping to the ground again.
"I couldn't believe what I'd seen. It was quite bizarre."
The caravan was extensively damaged. The trampoline was the third the Christiansens had lost to high winds.
"I don't think we'll have a fourth. I think lesson learnt," Mr Christiansen said.
Other Cromwell residents also reported items being lifted off the ground by powerful, circular winds on Friday evening.
In January 2009, mini tornadoes tore off a section of the Bannockburn Hotel's roof, and in July of that year, a whirlwind whipped through an area north of Cromwell, ripping apart an implement shed and lifting an entire roof off a barn.