Dunedin records wettest day since 1923 with 2.4 times the average October rainfall in 40 hours, New Zealand
Dunedin has recorded its wettest day since 1923, with a staggering 130.8 mm (5.15 inches) of rain falling in just 24 hours between October 3 and October 4, 2024. As a result, the region experienced widespread flooding, with authorities placing Dunedin and the Clutha districts under a state of emergency.
Image credit: JMA/Himawari-9, Zoom Earth, The Watchers. Acquired at 22:50 UTC on October 4, 2024
A moisture plume, generated by a low-pressure system over the Tasman Sea, brought heavy rainfall to parts of New Zealand, particularly affecting the Otago region.
One of the worst affected areas was Dunedin where 130.8 mm (5.15 inches) of rain fell between 09:00 LT on October 3 and 09:00 LT on October 4. The last time the region saw such rainfall was in 1923.
Over a 40-hour period, approximately 74 days’ worth of rain fell in Dunedin, with 143 mm (5.63 inches) recorded between 16:00 LT on October 2 and 08:00 LT on October 4. This amount is roughly 2.4 times the city’s typical October rainfall.
As of October 5, Dunedin had received 178 mm (7.01 inches) of rain, which is about 105% of its total spring rainfall. Meanwhile, Balclutha recorded 134 mm (5.28 inches), reaching 84% of its seasonal rainfall.
The plume, which formed in late September and originated around 3 000 km (1 864 miles) away in Fiji, began delivering heavy rain to the region on October 1. By October 3, Dunedin had already received 75% of its average monthly rainfall of 60 mm (2.36 inches).
As a result, the region experienced widespread flooding, with authorities placing Dunedin and the Clutha districts under a state of emergency.
Local media are reporting flooded houses in Dunedin, evacuations, and water and cell tower outages in some areas.
130 roads and highways across Otage were closed on Saturday morning, October 5, with widespread slips, blocks, and damage cutting off several communities from the rest of the region.
Authorities have urged people not to venture out if not necessary.
References:
1 Otago floods: Counting the damage – What you need to know – RNZ – October 5, 2024
I am an Assistant Editor and Severe Weather & Science Journalist at The Watchers, specializing in real-time severe weather coverage, geophysical event reporting, and research-driven scientific analysis. You can reach me at rishav(at)watchers(.)news.
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