Why the forecasts didn’t forecast this: Two floods, man missing, state of emergency
Tuesday, 21 April 2026
Two short, sharp hits of damaging and flooding rain, a missing man, a Wellington regional state of emergency and a city caught off guard – but experts say the technology for better predictions simply does not yet exist.
The torrential rain that dumped on Wellington on Monday caused more than 150 weather-related events - landslips and flooding across many parts of Wellington including Karori where a man remains missing.
Flights have been cancelled, schools closed and Wellington City Council facilities are also all closed on Tuesday. A regional state of emergency remains in place as most of Wellington, Wairarapa and the Tararua Ranges are under a red heavy rain warning until midnight.
The Wellington Region Emergency Management Office on Monday said people in low-lying and flood-prone areas should evacuate for 24 hours.
Victoria University climate science professor James Renwick said, with climate change putting more moisture into the air, we could expect more sudden thundery, flooding downpours.
Renwick, who knew of no current technology that could give better predictions of the sudden weather events, said there was hope. Artificial Intelligence was showing promise and more research into forecasting could only help.
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“More funding for research would help,” Canary Innovation social scientist and warnings consultant Sally Potter said.
After a weekend when Cyclone Vaianu was forecast but didn’t affect the lower North Island, two bands of torrential rain did.
Stokes Valley in Lower Hutt and Porirua suffered severe flooding on Saturday. And early on Monday morning, it was Wellington City’s turn with 77mm of rain in a single hour from 3am to 4am in Berhampore. Homes around the city were flooded, a car was tossed around and severely damaged in a south coast stream, and large slips came down in Kingston.
The Wellington Civil Defence Emergency Management Group, which includes mayors, confirmed a regional state of emergency was declared at 1.30pm on Monday. The declaration allows powers that would not normally be available such as forcing people to leave their homes, access to resources and the ability to close roads.
The Saturday and Monday storms caught mayors – Anita Baker in Porirua, Ken Laban in Hutt City and Andrew Little in Wellington – off guard with each saying warnings were far from sufficient.
How better to calculate risks associated with the increasing numbers of unpredictable weather events was something that needed to be looked at, Little said.
“We seem to get warnings of things and do a lot of preparation, and not much happens and then we have incidents like this, where there's no warning and then it hits us.”
Earth Science’s Chester Lampkin said accurate forecasting was a matter of both resources and money. Unlike the United States, New Zealand didn’t have high‑resolution models that could pick up convective events more precisely.
“What we got was a thunderstorm that sat right over the southern part of Wellington City. What are the chances of that happening? Well, we knew that there was going to be some heavy rain in the area. That was pretty well forecast, but we didn't know exactly where those thunderstorms would pop up.
Forecasting had come a long way in the last decade but it was still easy to miss “freakish” events.
“For Wellington and the Hutt Valley it's just really been a string of bad luck. If those thunderstorms formed 10 kilometres to the east, we wouldn't be having this conversation. It would have been a nothing burger.”
Police on Monday confirmed a search and rescue operation was underway after Philip Sutton, in his 60s, went missing on South Karori Rd at 7.15 and could not be contacted. His property was affected by flood waters and debris, police said.