Exercise Tahu-nui-a-Rangi 2025

Exercise Tahu-nui-a-Rangi aims to improve New Zealand’s ability to respond to and recover from a significant Space Weather Event.

What is space weather?

In Aotearoa New Zealand, a large space weather event could damage electricity network, and all or part of the national grid could be turned off to protect it. This would cause lengthy power cuts and disrupt important everyday services like broadcasting, banking systems, traffic lights, petrol and diesel pumps and supply of food and other items to supermarkets.

Learn more about space weather:

Video: What is space weather? (sws.bom.gov.au)

Space weather (getready.govt.nz)

Our hazards: Space weather (.pdf 10mb)

What is Exercise Tahu-nui-a-Rangi?

Exercise Tahu-nui-a-Rangi 2025 is a national (Tier 4) exercise under the National Exercise Programme. This exercise will simulate the impacts of a severe space weather event on New Zealand's critical infrastructure, communication systems, and essential services.

The exercise will take place over two main days: 5 November and 6 November 2025. It will test New Zealand's readiness to respond to and recover from the cascading effects of a space weather event, ensuring robust coordination across agencies and sectors.

Tahu-nui-a-Rangi translates to: “The great fire of the Sky Father (Rangi)” or the Aurora Australis, which is a product of Space Weather.

Why do we need Exercise Tahu-nui-a-Rangi?

Exercising is a core part of readiness and helps identify gaps and issues. The identified lessons are integrated into plans and procedures. They improve our ability to respond to and recover from emergencies.

This exercise will help identify gaps in our preparedness, improve interagency coordination, and ensure that New Zealand is ready to respond to and recover from such an event.