20-25 years
High rainfalls and flooding were experienced throughout Northland and northern Auckland.
A flow remained very anticyclonic until 6am on the 17th, when a north-south front suddenly appeared and a trough in the Tasman Sea exhibited a slight negative tilt.
More than 200 mm (20.0 cm) of rain fell in some areas of Northland and northern Auckland on the 16th.
The ARI in some places exceeded a 100 year event.
High rainfall and thunderstorms caused flooding in Northland on the 16th.
Power supplies and telephone communications were disrupted.
Road acess was cut between Broadwood and Runa Runa and Pawarenga.
Northland received up to 16 in (40.6 cm) of rain in 24 hours.
The estimated return period was 25 years.
Roads were cut. The Mangakahia route between Kaikohe and Whangarei was flooded.
The railway was blocked for 24 hours.
Houses, shops and farms were flooded.
The bridge at Awarua was under water.
Dargaville recorded 3.02 in (7.7 cm) of rain in 24 hours on the 16th.
Glenberrie recorded 6.27 in (15.9 cm) of rain in 24 hours on the 16th.
Glenberrie recorded 2.5 in (6.4 cm) of rain in 24 hours on the 17th.
Hikurangi recorded 4.62 in (11.7 cm) of rain in 24 hours on the 16th.
Hikurangi recorded 4.70 in (11.9 cm) of rain in 24 hours on the 17th.
On the 16th and 17th, high intensity rainfall fell for 5-6 hours in a straight belt between Hukerenui and Lewis Bridge (over the Wairua River).
A flash flood of 20-year frequency occurred.
The railway was blocked for 24 hours.
The flow of water from the hills west of the Hikurangi swamp exceeded the capacity of every culvert and bridge on the road west of the swamp. A bridge was also washed out.
A total of 12,500 acres (5059 ha) of land was inundated.
Heavy damage was done to fences by floating debris. 1,500 acres (6.07 km^2) of paddock in the swamp catchment had to be regrasssed.
Some stock was lost.
At Hukerenui, there was 10 ft (3.0 m) of water over both the railway line and State Highway 1.
A goods train was derailed at Hukerenui.
The approaches to a bridge north of Hukerenui were washed out.
Stock losses were heavy north of SH1 between Hukerenui and Waiotu.
Kaikohe recorded 7.05 in (17.9 cm) of rain in 24 hours on the 16th.
Mangamutu Stream at the lower end of the borough was a raging torrent.
Hundreds of acres of low-lying land was under water.
Kokopu received about 400 mm (40.0 cm) of rain in 24 hours.
The Manganui River at the Permanent Station reached a gauge height of 8.062 m on the 18th.
The Manganui River at the Permanent Station had a peak discharge of 232 cumecs on the 18th, with a catchment area of 417 km^2.
Maungakaramea recorded 10.5 in (26.7 cm) of rain in 24 hours on the 16th.
Maungatapere recorded 10.01 in (25.4 cm) of rain in 24 hours on the 16th.
The Opahi at the Pond reached a gauge height of 3.542 m on the 17th.
The Opahi at the Pond had a peak discharge of 76.4 cumecs on the 17th, with a catchment area of 10.4 km^2.
Puhipuhi recorded 9.01 in (22.9 cm) of rain in 24 hours on the 16th.
Puhipuhi recorded 3.1 in (7.9 cm) of rain in 24 hours on the 17th.
Rawene was completely isolated from road access.
Ruatangata recorded 13.23 in (33.6 cm) of rain in 24 hours on the 16th.
Ruatangata recorded 1.67 in (4.2 cm) of rain in 24 hours on the 17th.
Russell recorded 3.86 in (9.8 cm) of rain in 24 hours on the 16th.
A washout occurred at Taumarere.
The Tauraroa school was closed.
The Titoki school was closed.
Towai recorded 6.16 in (15.6 cm) of rain in 24 hours on the 16th.
Towai recorded 1.50 in (3.8 cm) of rain in 24 hours on the 17th.
Waikiekie recorded 6.74 in (17.1 cm) of rain in 24 hours on the 16th.
The Wairua River at the Wairua Bridge reached a gauge height of 5.465 m on the 17th.
The Wairua River at the Wairua Bridge had a peak discharge of 645 cumecs on the 17th, with a catchments area of 707 km^2.
Waitangi State Forest recorded 4.39 in (11.2 cm) of rain in 24 hours on the 16th.
There was 3 ft (90 cm) of water in a strong current across the road at Whakapara.
The Whakapara River at the State Highway Bridge reached a gauge height of 8.352 m on the 17th.
The Whakapara River at the State Highway Bridge had a peak discharge of 273 cumecs on the 17th, with a catchment area of 163 km^2.
Whau Valley recorded 7.3 in (18.5 cm) of rain in 24 hours on the 16th.
Rail traffic was cut north and south of Whangarei.
State Highway 14 from Whangarei to Maungatapere was blocked.
12 ft (3.7 m) of water swept across one site.
Whenuapai recorded 260 mm (26.0 cm) of rain in 24 hours (Return Period over 150 years).
Whenuapai recorded 107 mm (10.7 cm) of rain in one hour (Return Period well over 150 years). The one-hour downpour broke a 35-year record.
20-25 years
High rainfalls and flooding were experienced throughout Northland and northern Auckland.
A flow remained very anticyclonic until 6am on the 17th, when a north-south front suddenly appeared and a trough in the Tasman Sea exhibited a slight negative tilt.
More than 200 mm (20.0 cm) of rain fell in some areas of Northland and northern Auckland on the 16th.
The ARI in some places exceeded a 100 year event.
High rainfall and thunderstorms caused flooding in Northland on the 16th.
Power supplies and telephone communications were disrupted.
Road acess was cut between Broadwood and Runa Runa and Pawarenga.
Northland received up to 16 in (40.6 cm) of rain in 24 hours.
The estimated return period was 25 years.
Roads were cut. The Mangakahia route between Kaikohe and Whangarei was flooded.
The railway was blocked for 24 hours.
Houses, shops and farms were flooded.
The bridge at Awarua was under water.
Dargaville recorded 3.02 in (7.7 cm) of rain in 24 hours on the 16th.
Glenberrie recorded 6.27 in (15.9 cm) of rain in 24 hours on the 16th.
Glenberrie recorded 2.5 in (6.4 cm) of rain in 24 hours on the 17th.
Hikurangi recorded 4.62 in (11.7 cm) of rain in 24 hours on the 16th.
Hikurangi recorded 4.70 in (11.9 cm) of rain in 24 hours on the 17th.
On the 16th and 17th, high intensity rainfall fell for 5-6 hours in a straight belt between Hukerenui and Lewis Bridge (over the Wairua River).
A flash flood of 20-year frequency occurred.
The railway was blocked for 24 hours.
The flow of water from the hills west of the Hikurangi swamp exceeded the capacity of every culvert and bridge on the road west of the swamp. A bridge was also washed out.
A total of 12,500 acres (5059 ha) of land was inundated.
Heavy damage was done to fences by floating debris. 1,500 acres (6.07 km^2) of paddock in the swamp catchment had to be regrasssed.
Some stock was lost.
At Hukerenui, there was 10 ft (3.0 m) of water over both the railway line and State Highway 1.
A goods train was derailed at Hukerenui.
The approaches to a bridge north of Hukerenui were washed out.
Stock losses were heavy north of SH1 between Hukerenui and Waiotu.
Kaikohe recorded 7.05 in (17.9 cm) of rain in 24 hours on the 16th.
Mangamutu Stream at the lower end of the borough was a raging torrent.
Hundreds of acres of low-lying land was under water.
Kokopu received about 400 mm (40.0 cm) of rain in 24 hours.
The Manganui River at the Permanent Station reached a gauge height of 8.062 m on the 18th.
The Manganui River at the Permanent Station had a peak discharge of 232 cumecs on the 18th, with a catchment area of 417 km^2.
Maungakaramea recorded 10.5 in (26.7 cm) of rain in 24 hours on the 16th.
Maungatapere recorded 10.01 in (25.4 cm) of rain in 24 hours on the 16th.
The Opahi at the Pond reached a gauge height of 3.542 m on the 17th.
The Opahi at the Pond had a peak discharge of 76.4 cumecs on the 17th, with a catchment area of 10.4 km^2.
Puhipuhi recorded 9.01 in (22.9 cm) of rain in 24 hours on the 16th.
Puhipuhi recorded 3.1 in (7.9 cm) of rain in 24 hours on the 17th.
Rawene was completely isolated from road access.
Ruatangata recorded 13.23 in (33.6 cm) of rain in 24 hours on the 16th.
Ruatangata recorded 1.67 in (4.2 cm) of rain in 24 hours on the 17th.
Russell recorded 3.86 in (9.8 cm) of rain in 24 hours on the 16th.
A washout occurred at Taumarere.
The Tauraroa school was closed.
The Titoki school was closed.
Towai recorded 6.16 in (15.6 cm) of rain in 24 hours on the 16th.
Towai recorded 1.50 in (3.8 cm) of rain in 24 hours on the 17th.
Waikiekie recorded 6.74 in (17.1 cm) of rain in 24 hours on the 16th.
The Wairua River at the Wairua Bridge reached a gauge height of 5.465 m on the 17th.
The Wairua River at the Wairua Bridge had a peak discharge of 645 cumecs on the 17th, with a catchments area of 707 km^2.
Waitangi State Forest recorded 4.39 in (11.2 cm) of rain in 24 hours on the 16th.
There was 3 ft (90 cm) of water in a strong current across the road at Whakapara.
The Whakapara River at the State Highway Bridge reached a gauge height of 8.352 m on the 17th.
The Whakapara River at the State Highway Bridge had a peak discharge of 273 cumecs on the 17th, with a catchment area of 163 km^2.
Whau Valley recorded 7.3 in (18.5 cm) of rain in 24 hours on the 16th.
Rail traffic was cut north and south of Whangarei.
State Highway 14 from Whangarei to Maungatapere was blocked.
12 ft (3.7 m) of water swept across one site.
Whenuapai recorded 260 mm (26.0 cm) of rain in 24 hours (Return Period over 150 years).
Whenuapai recorded 107 mm (10.7 cm) of rain in one hour (Return Period well over 150 years). The one-hour downpour broke a 35-year record.