Insurance companies have already forked out more for extreme weather-related claims than this time last year.
July alone saw more than 6000 claims across the motu, totalling $43 million.
A torrent of mud cascaded into a small mountain community in Southern California.
"It looked like fast-flowing lava," said California resident Susan Novacoski.
The latest carnage coincides with a United Nations (UN) report saying disasters are the price of humanity's fossil fuel addiction.
"The number of weather, climate and water-related disasters has increased by a factor of five over the past 50 years. Daily losses total more than US$200 million," said UN's secretary-general António Guterres.
In Aotearoa, Insurance Council of New Zealand chief executive Tim Grafton said the cost of climate change is relentless too.
"The costs are going up and this speaks to the need to reduce the risks from climate change."
Extreme weather-related claims, mostly from flooding but also fires, hailstorms and tornadoes, show a striking trend upwards in the past decade.
From 2013 to 2017, claims related to extreme weather totalled $517 million. Compared to the last five years, they've tipped over $1.2 billion.
Last year was a record for weather-related claims at $324 million, and this year has already hit $245 million - $20 million more than this time last year.
"We don't want to see continual development in dumb places which is just going to create future problems," said Grafton.
"There's a role there for Government to work with the insurance industry to make sure we've got better information, better data available about these kinds of risks," Climate Change Minister James Shaw said.
A proposed law change will see planning rules guide people away from building in high-risk places, because insurance costs continuing on the trajectory we see now is unsustainable - for insurance companies and households.
