"Cyclone Gabrielle on steroids": More extreme storms coming for NZ

Embargoed until: Publicly released: 2026-03-30 14:14

New Zealand

NASA (CC0)

Previously rare extreme rains could happen two to three times more often across much of NZ in future, new modelling suggests. The researchers simulated future weather conditions under different climate change scenarios. The simulations showed possible massive, multi-region, multi-day storms that resemble some of New Zealand's most devastating cyclones. In some parts of the country, rainfall during these future extreme events could be up to 300% higher than in previous storms, but the researchers said it was challenging to predict exactly where these events might occur.

News release

From: Luke Harrington, Climate Scientist, and Senior Lecturer, Waikato University

"We've had some big rainfall events happen quite often across NZ in recent years (and months). And yet, the climate system is also super noisy, which means that some regions experienced their biggest rainfall events many decades ago. So how do we contextualise this noise when thinking about future warming scenarios? Well, our best-guess estimate, for a middle-of-the-road (SSP2-4.5) emissions scenario, is that you've got a ~50% chance of experiencing at least a 50% rise in the number of impactful rainfall events by the end of the twenty-first century relative to 1985-2014. But also a ~30% chance of living in a place which sees twice as many events, and a ~10% chance of living in a place which sees three times as many events. Now, what is the difference between those places which see a three-fold increase and the other places which see only a 50% increase in the number of bad events? Honestly, not much really, it's largely down to good or bad luck (i.e. internal variability).

"As global temperatures continue to rise, so do the risks of experiencing massive, multi-region, multi-day rainfall events with the potential to cause devastating impacts. We highlight two such record-shattering events which could plausibly happen in the future: one which resembles Cyclone Gabrielle on steroids; the other is an event we haven't really seen before. It kind of resembles the May 1923 Canterbury storm (one of the most statistically anomalous events we found in the historical station records) albeit making impact quite a bit further to the south: that is, with Christchurch right in the firing line."