2004

Monday, 10 January 2005

Summary

Very stormy at times Devastating floods and extremely high rainfall in several North Island regions High winds and late winter blizzards Very wet in some areas and cool

The New Zealand climate record of 2004 reflected a nation prone to extreme climatic events. Forest fires, flooding assessed as the worst in living memory, tornadoes, blizzards, hailstorms and persistent storms with gale force winds characterised a year of dramatic climate extremes. Principal Scientist Dr Jim Salinger, of the NIWA National Climate Centre, says the year produced new records for rainfall, temperatures and sunshine in most months and was dominated by strong stormy westerly and south westerly winds more frequent than normal.

"There were rogue qualities in the overall climate pattern. These included the anticyclones that dominated in January and then gave way to stormy westerlies and south westerlies in February which produced the most extreme rainfall and flooding experienced in Manawatu and Taranaki since the 1920s. Overall the year was one of the wettest on record in parts of the Bay of Plenty, some eastern North Island sites, Manawatu, Kapiti, Upper Hutt and Wairarapa. Few districts escaped the storms and heavy rainfall that battered most of the country at different times."

"Anticyclones predominated in April and July, with northerlies or northwesterlies in May and June. Weak El Niño conditions appeared in the Equatorial Pacific during August, and strong southwesterlies and deep depressions in the vicinity of the Chatham Islands influenced the climatic patterns through to December. The final month produced a finale with the strongest airflows from the south and south west on record"

The year began with very high temperatures accompanied by high winds, producing life threatening forest fires in early January in Canterbury. These gave way to record rainfall in Taranaki/Wanganui making flooding the dominant climate hazard by the end of February. June was very warm and July brought another bout of flooding in the Bay of Plenty, whilst the south stayed extremely dry. August received very persistent cold southerlies producing blizzards and high winds. Persistent strong cold stormy south westerlies dominated the remainder of the year, with December being unusually cold.

"For the year there were at least 28 heavy rainfall events of which 12 produced floods, mainly in the North Island. The February storms were disastrous, bringing widespread damage to the Wanganui-Manawatu region assessed at over $300 million, and the July floods in eastern Bay of Plenty were reported to be the worst in the district in living memory. High country regions were affected by many snowfall events from autumn through spring, one as early as March, with several resulting in transport cut and lambs lost", said Dr Salinger. Of the 19 high wind events, the 15 February southerly storm and the damaging southerly winds of 17-18 August, along with a tragically destructive tornado a few days earlier, were most severe. There were also four damaging hailstorms.

NIWA analyses of month-by-month records and preliminary end of year data show:

• The year’s national average temperature was 12.3°C (0.3°C below normal), the lowest since 1993.
• The highest annual mean temperature recorded for the year was 15.3°C recorded at Whangarei.
• The highest recorded extreme air temperature for the year was 38.4°C recorded at Darfield on New Year’s Day, equal to the highest January temperature on record for the South Island .
• A late-autumn heat wave occurred in Hawke’s Bay on 2 May, with a record 27.3°C at Napier, a new May all-time record for the North Island.
• June was the 5th warmest since measurements commenced in the 1850s.
• The lowest air temperature for the year was –12.0°C, recorded at Fairlie on 16 August, the 3rd lowest August air temperature since records commenced in 1925.
• December was the 5th coldest on record.
• The driest rainfall recording locations were Middlemarch in eastern Otago with 441 mm of rain for the year, followed by Alexandra with 492 mm.
• Christchurch was the driest of the four main centres with 643mm and Wellington the wettest with 1447 mm. Auckland received 1331 mm and Dunedin 765 mm.
• Of the regularly reporting gauges, the Cropp River gauge in Westland, inland in the headwaters of the Hokitika River, recorded the highest rainfall with a 2004 annual total of 10960 mm.
• Christchurch was the sunniest of the four main centres with 2096 sunshine hours, followed by Wellington (2073 hours) and Auckland (2066 hours). Dunedin recorded 1746 hours. Nelson was the sunniest centre in 2004, recording 2457 hours, followed by Blenheim with 2393 hours, and then Tauranga with 2360 hours.
• The highest recorded wind gust for the year was 183 km/h at Baring Head on 18 August, with hurricane force southerlies and mean speeds as high as 140 km/h.

Full report

Climate Summary for 2004 (PDF 148 KB)

For further information, please contact:

Dr Jim Salinger – Principal Scientist, Climate NIWA National Climate Centre – Auckland Phone +64 9 375 2053 [email protected]

Stuart Burgess – Climatologist NIWA National Climate Centre – Wellington Phone +64 4 386 0569 [email protected]

Geoff Baird – Communications Manager Phone +64 4 386 0543 [email protected]

Acknowledgement of NIWA as the source is required.