Aotearoa NZ · Climate
NZ Cyclones & Flooding
SevereEx-tropical cyclones and extreme rainfall causing flooding, slips and infrastructure failure across New Zealand.
- Likelihood
- Multiple significant events per decade
- Impact
- Severe regionally; billions in losses
- Horizon
- Cyclone season November to April
Background
What this actually is
New Zealand typically sees one ex-tropical cyclone a year come within 550 km. Warmer Tasman and Coral Sea temperatures let these systems retain strength further south than they historically could.
The 2023 Auckland Anniversary floods and Cyclone Gabrielle three weeks later killed 15 people and caused an estimated $9-14.5 billion in damage. Hawke's Bay and Tairāwhiti lost road, power and communications for weeks.
The compounding factor is that saturated ground from one event makes the next one far worse — slips, river breaches and stopbank failures all follow prior rainfall.
Aotearoa
What it means for New Zealand
NZ's terrain converts rainfall into flash flooding and landslides very quickly. Many communities have one road in. Forestry slash on the East Coast has repeatedly dammed and destroyed bridges. Telecommunications sites have limited battery backup, so contact is often lost early.
Watch for
Early warning signs
- MetService red warnings and Severe Weather Watches
- Fiji Meteorological Service tropical cyclone tracks heading south
- Regional council river level alerts
- Warm Tasman Sea anomalies going into summer
Action
How to prepare
- 01
Grab bag by the door and a household plan everyone knows
- 02
Never drive through floodwater — it is the leading cause of flood deaths
- 03
Charge devices and fill water containers when a red warning is issued
- 04
Clear gutters and drains before the season, not during the storm
Go deeper
Where to find more information
In an emergency
New Zealand's official channels
- Get Ready — household preparedness
- Civil Defence / NEMA
- GeoNet — quakes, volcanoes, tsunami
- MetService severe weather warnings
In a life-threatening emergency call 111. RNZ National is New Zealand's designated lifeline broadcaster — keep a battery radio.
Connected
Related threats
Get prepared
Want to do something useful with this information?
Preparing.nz is a practical guide for New Zealanders who want to be ready for the unexpected — earthquakes, storms, power cuts, pandemics and more.