Backgrounder

Backgrounder

Bleak December ends a turbulent year

Difference from mean sea level pressure (hectopascals) in December – the month was dominated by some of the strongest westerly and southwesterly wind flows on record. Map: Jim Renwick

The year 2004 will not be forgotten quickly. Extreme weather conditions, on many occasions unprecedented in the climate record, made it a hazardous year for weather and climate sensitive industries, and may have prompted revised assessments of natural hazard risk. Some examples:

January

Rainfall totalling 74 mm was measured in one day at St Bathans (Otago), with reports of flash flooding in the Wanaka district. Early in the month, record high air temperatures were recorded in many localities.

February

The worst rainfall and floods since the 1920s caused $300 million worth of damage in Wanganui-Manawatu. More than 1000 mm of rain fell in the Tararua Ranges. Thousands of households were without gas, electricity, and water for several days. In a separate event, 30 houses were flooded in Turangi as the Tongariro River overflowed its banks. Strong westerly winds buffeted the North Island throughout the month, with record numbers of days with gale force winds.

March

Dargaville recorded its lowest rainfall since records began in 1943, and Paeroa its second lowest March rainfall since 1914. An unusually early snowfall in the central North Island closed the Desert Road.

April

Violent electrical storms caused power outages on the Whangaparaoa Peninsula. In a separate event, a thick layer of hailstones (up to 20 cm deep in places) whitened the ground in Wanganui, damaging roofs and causing disruptions to traffic.

May

Strong winds damaged houses in Wellington. A number of localities recorded their highest maximum temperatures on record for May.

June

Gales in Hawke’s Bay brought down trees and cut power to 11 000 homes.

July

Eastern Bay of Plenty floods were reported to be the worst in living memory. More than 17 000 people faced shortages of drinking water. Hail storms battered Hokitika and New Plymouth. Elsewhere, July was unusually frosty.

August

High rainfall and a windstorm caused many slips in the Hutt Valley. Buses were cancelled, and several schools were closed. Thousands of commuters could not make it to work. Wellington Airport experienced over 20 consecutive hours of strong gale force winds, with damage to buildings, in the worst southerly storm for more than a decade.

September

Snowfall in Otago and Southland, and later in Canterbury, caused widespread loss of newborn lambs.

October

Hail storms occurred in Wairarapa and Hawke’s Bay, damaging fruit – one orchardist noting it was 'the worst he had seen.'

November

Thick hail blocked guttering and melting water flooded several shops and caused power outages in Oamaru.

December

Gale force southerlies pounded southern and eastern areas. Snowfall occurred as low as 600 m in the South Island, with a light fall on the Desert Road in the central North Island. Temperatures were 6-8 °C below normal in many southern and eastern regions during the event. Hailstones ruined fruit in parts of Auckland, Hawke’s Bay, Tasman, and Canterbury. Many places recorded record-breaking low mean temperatures.


Summer snow line on Mt Taranaki – fresh snow in December slowed the snow line’s normal retreat. (Cover photo: Wendy St George)