NZ Historic Weather Events Catalog

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July 1998 New Zealand Flooding ( 1998-07-01 )

Heavy rain fell in Waikato, Bay of Plenty, Wellington, Marlborough, Tasman-Nelson and the West Coast, bringing flooding and slips to some places. Te Kuiti recorded rainfall with a return period of over 100 years.

New Zealand

Multi HazardMulti Hazard
Duration:   2  days - From the 1st to the 2nd of July.
Comments:

CauseOn the 1st, a deep, complex depression developed in the northern Tasman Sea. A strong northerly flow developed ahead of this depression, dragging moist, humid air towards New Zealand. On the 2nd, an associated cold front crossed the North Island. A very strong, moist northerly flow ahead of the front was responsible for the heavy rain in northern districts, and the wind flow was at the ideal angle of onshore flow into the Bay of Plenty region. A cold southerly change followed the depression as it passed to the east, and this brought the period of heavy rain to Wellington that day.

FloodingFlooding
Comments:

CommentOn the 1st and 2nd, a northerly storm moved across the North Island, bringing floods to a number of districts.

Heavy RainHeavy Rain
Comments:

CommentHigh rainfall occurred throughout Coromandel, Bay of Plenty, Tongariro, Taupo, Buller, Golden Bay, Marlborough and Nelson on the 1st.

Physical CharacteristicSome places received over 200 mm (20.0 cm) of rain.

CommentHeavy rain was initially in the northerly overnight on the 1st/2nd and then in a more serious southerly in late morning on the 2nd.

North Island

Multi HazardMulti Hazard at North Island
Comments:

CauseA blocking anticyclone to the north-east of the North Island and a low pressure area to the west. Surface airflow was predominantly from the north-west. A combination of abundant moisture and high winds on northern slopes resulted in orographical enhancement producing widespread precipitation throughout Waikato and the Central North Island.

South Island

Heavy RainHeavy Rain at South Island
Comments:

CommentThe northerly rain storm's initial impact occurred in the South Island's West Coast, Nelson and Marlborough.

Waikato

FloodingFlooding at Waikato
Comments:

CommentA sequence of storm events over the catchments of Lake Taupo and the middle reaches of the Waikato River led to extensive and prolonged flooding downstream of Hamilton.

CommentThe July 1998 events were extreme, with return periods of inflows to the Waikato between Taupo and Karapiro between 15-80 years.

CommentThe Mangakino and Waipapa catchments on the western side of the river experienced record floods, nearly twice as large as any recorded in the previous 35 years.

CommentReturn periods between 2-10 years were common for the Waikato tributary area (between Lake Taupo and Karapiro).

CommentReturn periods for the Rangitaiki and Tongariro catchments were as high as 20 years.

CommentThe events occurred in winter, meaning enhanced catchment wetness and potentially greater runoff, and intense rainfall was very localised.

Heavy RainHeavy Rain at Te Kuiti
Map Location: -38.3277 175.172348
Comments:

CommentThe Te Kuiti gauge recorded a three-day rainfall with a return period of 33 years.

CommentThe Te Kuiti gauge recorded a seven-day rainfall with a return period of 100 years. >>100 years at 14 days)

CommentThe Te Kuiti gauge recorded a 14-day rainfall with a return period of more than 100 years.

Wellington

Multi HazardMulti Hazard at Wellington
Comments:

Affected LifelineBoth State Highways out of Wellington were affected by slips and floods on the 1st.

FloodingFlooding
Comments:

Affected LifelineSewerage problems occurred in Wellington on the 1st.

Marlborough

Multi HazardMulti Hazard at Marlborough
Comments:

ImpactThe worst affects were in rural areas of Nelson and Marlborough Sounds. Flooding and slips affected properties.

Affected LifelineRivers ran high, and flooding and slips affected roads.

Tasman-Nelson

FloodingFlooding at Tasman-Nelson
Comments:

Affected LifelineSewerage problems occurred in Nelson on the 1st.

Multi HazardMulti Hazard
Comments:

ImpactThe worst affects were in rural areas of Nelson and Marlborough Sounds. Flooding and slips affected properties.

Affected LifelineRivers ran high, and flooding and slips affected roads.

West Coast

Multi HazardMulti Hazard at West Coast
Comments:

ImpactFlooding and slips affected properties.

Affected LifelineRivers ran high, and flooding and slips affected roads.

Heavy RainHeavy Rain at Ahaura River
Map Location: -42.491019 171.801131
Comments:

Physical CharacteristicAhaura recorded daily totals for seven days prior to the event of: 70 mm, 68 mm, 0 mm, 0 mm, 0 mm, 23 mm, and 20 mm.

Physical CharacteristicAhaura recorded a maximum intensity of 7 mm (0.7 cm) - the highest one hour rainfall intensity recorded in the 48 hours prior to event peak.

FloodingFlooding
Comments:

Peak River LevelThe Ahaura River at the Gorge recorded a peak level of 4.254 m on the 1st (Return Period approximately two years).

FloodingFlooding at Dobson
Map Location: -42.451971 171.314964
Comments:

Peak River LevelThe Grey River at Dobson recorded a peak level of 5.441 m on the 1st (Return Period approximately two years).

Heavy RainHeavy Rain at Moana
Map Location: -42.575021 171.485214
Comments:

Physical CharacteristicMoana recorded daily totals for seven days prior to the event of: 80 mm, 33 mm, 0 mm, 0 mm, 1 mm, 33 mm, and 33 mm.

Physical CharacteristicMoana recorded a maximum intensity of 7 mm (0.7 cm) - the highest one hour rainfall intensity recorded in the 48 hours prior to event peak.

Heavy RainHeavy Rain at Waipuna
Map Location: -42.320377 171.716458
Comments:

Physical CharacteristicWaipuna recorded daily totals for seven days prior to the event of: 56 mm, 59 mm, 0 mm, 0 mm, 0 mm, 21 mm, and 12 mm.

Physical CharacteristicWaipuna recorded a maximum intensity of 8 mm (0.8 cm) - the highest one hour rainfall intensity recorded in the 48 hours prior to event peak.

FloodingFlooding
Comments:

Peak River LevelThe Grey River at Waipuna recorded a peak level of 4.053 m on the 1st (Return Period less than two years).

References

Henderson, R.; Thompson, S. Waikato Tributary floods of July 1998.
Major weather events in New Zealand, Floods and Rainfall, Floods to 30 Sep 2005.
Major weather events in New Zealand, Floods and High Rainfall, Floods to 31st July 2006.
Major weather events in New Zealand, Floods and High Rainfall to 31st May 2006.
www.metservice, notable weather events.govt.nz.
Southland Regional Council (CD).

July 1998 New Zealand Flooding ( 1998-07-01 )

Heavy rain fell in Waikato, Bay of Plenty, Wellington, Marlborough, Tasman-Nelson and the West Coast, bringing flooding and slips to some places. Te Kuiti recorded rainfall with a return period of over 100 years.

New Zealand

Multi HazardMulti Hazard
Duration:   2  days - From the 1st to the 2nd of July.
Comments:

CauseOn the 1st, a deep, complex depression developed in the northern Tasman Sea. A strong northerly flow developed ahead of this depression, dragging moist, humid air towards New Zealand. On the 2nd, an associated cold front crossed the North Island. A very strong, moist northerly flow ahead of the front was responsible for the heavy rain in northern districts, and the wind flow was at the ideal angle of onshore flow into the Bay of Plenty region. A cold southerly change followed the depression as it passed to the east, and this brought the period of heavy rain to Wellington that day.

FloodingFlooding
Comments:

CommentOn the 1st and 2nd, a northerly storm moved across the North Island, bringing floods to a number of districts.

Heavy RainHeavy Rain
Comments:

CommentHigh rainfall occurred throughout Coromandel, Bay of Plenty, Tongariro, Taupo, Buller, Golden Bay, Marlborough and Nelson on the 1st.

Physical CharacteristicSome places received over 200 mm (20.0 cm) of rain.

CommentHeavy rain was initially in the northerly overnight on the 1st/2nd and then in a more serious southerly in late morning on the 2nd.

North Island

Multi HazardMulti Hazard at North Island
Comments:

CauseA blocking anticyclone to the north-east of the North Island and a low pressure area to the west. Surface airflow was predominantly from the north-west. A combination of abundant moisture and high winds on northern slopes resulted in orographical enhancement producing widespread precipitation throughout Waikato and the Central North Island.

South Island

Heavy RainHeavy Rain at South Island
Comments:

CommentThe northerly rain storm's initial impact occurred in the South Island's West Coast, Nelson and Marlborough.

Waikato

FloodingFlooding at Waikato
Comments:

CommentA sequence of storm events over the catchments of Lake Taupo and the middle reaches of the Waikato River led to extensive and prolonged flooding downstream of Hamilton.

CommentThe July 1998 events were extreme, with return periods of inflows to the Waikato between Taupo and Karapiro between 15-80 years.

CommentThe Mangakino and Waipapa catchments on the western side of the river experienced record floods, nearly twice as large as any recorded in the previous 35 years.

CommentReturn periods between 2-10 years were common for the Waikato tributary area (between Lake Taupo and Karapiro).

CommentReturn periods for the Rangitaiki and Tongariro catchments were as high as 20 years.

CommentThe events occurred in winter, meaning enhanced catchment wetness and potentially greater runoff, and intense rainfall was very localised.

Heavy RainHeavy Rain at Te Kuiti
Map Location: -38.3277 175.172348
Comments:

CommentThe Te Kuiti gauge recorded a three-day rainfall with a return period of 33 years.

CommentThe Te Kuiti gauge recorded a seven-day rainfall with a return period of 100 years. >>100 years at 14 days)

CommentThe Te Kuiti gauge recorded a 14-day rainfall with a return period of more than 100 years.

Wellington

Multi HazardMulti Hazard at Wellington
Comments:

Affected LifelineBoth State Highways out of Wellington were affected by slips and floods on the 1st.

FloodingFlooding
Comments:

Affected LifelineSewerage problems occurred in Wellington on the 1st.

Marlborough

Multi HazardMulti Hazard at Marlborough
Comments:

ImpactThe worst affects were in rural areas of Nelson and Marlborough Sounds. Flooding and slips affected properties.

Affected LifelineRivers ran high, and flooding and slips affected roads.

Tasman-Nelson

FloodingFlooding at Tasman-Nelson
Comments:

Affected LifelineSewerage problems occurred in Nelson on the 1st.

Multi HazardMulti Hazard
Comments:

ImpactThe worst affects were in rural areas of Nelson and Marlborough Sounds. Flooding and slips affected properties.

Affected LifelineRivers ran high, and flooding and slips affected roads.

West Coast

Multi HazardMulti Hazard at West Coast
Comments:

ImpactFlooding and slips affected properties.

Affected LifelineRivers ran high, and flooding and slips affected roads.

Heavy RainHeavy Rain at Ahaura River
Map Location: -42.491019 171.801131
Comments:

Physical CharacteristicAhaura recorded daily totals for seven days prior to the event of: 70 mm, 68 mm, 0 mm, 0 mm, 0 mm, 23 mm, and 20 mm.

Physical CharacteristicAhaura recorded a maximum intensity of 7 mm (0.7 cm) - the highest one hour rainfall intensity recorded in the 48 hours prior to event peak.

FloodingFlooding
Comments:

Peak River LevelThe Ahaura River at the Gorge recorded a peak level of 4.254 m on the 1st (Return Period approximately two years).

FloodingFlooding at Dobson
Map Location: -42.451971 171.314964
Comments:

Peak River LevelThe Grey River at Dobson recorded a peak level of 5.441 m on the 1st (Return Period approximately two years).

Heavy RainHeavy Rain at Moana
Map Location: -42.575021 171.485214
Comments:

Physical CharacteristicMoana recorded daily totals for seven days prior to the event of: 80 mm, 33 mm, 0 mm, 0 mm, 1 mm, 33 mm, and 33 mm.

Physical CharacteristicMoana recorded a maximum intensity of 7 mm (0.7 cm) - the highest one hour rainfall intensity recorded in the 48 hours prior to event peak.

Heavy RainHeavy Rain at Waipuna
Map Location: -42.320377 171.716458
Comments:

Physical CharacteristicWaipuna recorded daily totals for seven days prior to the event of: 56 mm, 59 mm, 0 mm, 0 mm, 0 mm, 21 mm, and 12 mm.

Physical CharacteristicWaipuna recorded a maximum intensity of 8 mm (0.8 cm) - the highest one hour rainfall intensity recorded in the 48 hours prior to event peak.

FloodingFlooding
Comments:

Peak River LevelThe Grey River at Waipuna recorded a peak level of 4.053 m on the 1st (Return Period less than two years).

References

Henderson, R.; Thompson, S. Waikato Tributary floods of July 1998.
Major weather events in New Zealand, Floods and Rainfall, Floods to 30 Sep 2005.
Major weather events in New Zealand, Floods and High Rainfall, Floods to 31st July 2006.
Major weather events in New Zealand, Floods and High Rainfall to 31st May 2006.
www.metservice, notable weather events.govt.nz.
Southland Regional Council (CD).