This report presents a post-event hydrological analysis of the severe rainfall that affected eastern Northland between 18 and 22 January 2026. The event was characterised by two meteorologically distinct but successive rainfall systems that delivered extreme rainfall totals across the region. The resulting flooding caused widespread infrastructure damage, community evacuations, and a formal state of emergency declaration across Whangārei District. The events also caused extensive landslide and slip damage, confined to a relatively small area from Ōakura to Rawhiti across eastern Northland catchments. Post-event analysis of severe weather is important to provide a documented record of event characteristics, an objective assessment of rainfall rarity, and an evidence base to inform future hazard management.
Published: 25 May 2026