|Rainfall: Extremely wet, with
in the centre, south and west of the North Island
Wind: Much windier than usual, especially
the North Island
Temperatures: Below average overall,
in the South Island
Soil moisture: Significant deficits
central Marlborough, Canterbury, and Otago, but surpluses in some North
Sunshine: Extremely low in the south and
of the North Island
A total of 30 monthly
rainfall records were swept aside in a number of New Zealand
during the exceptionally wet February that produced widespread
and extensive infrastructure damage. Rainfall was very much above
in the south and west of the North Island from Waikato to Wellington,
Wairarapa. It was a month of climate extremes, with seven heavy
and at least three damaging high wind events. The reason for the
climate pattern was an unusually high number of depressions
(“lows”) to the south of the South Island, which often intensified
as they passed over New Zealand. There were very few of the
late summer anticyclones (“highs”). This pattern produced the strongest
westerlies in over 60 years of records for February over the North
and southwesterlies over the South Island.
More than 1000 mm was recorded in the
the month. This was due to a number of high rainfall-flood
events, on the 1st, and especially between the 14th
and 18th of February. The latter, produced the most
floods in the Wanganui, Manawatu/Rangitikei region for many decades, as
well as flooding in southern Hawkes’ Bay, Wairarapa, Lower Hutt, and
Hundreds of people were left homeless, considerable areas of farmland
inundated by silt and floodwaters, many rivers breached their banks,
and cattle stock were drowned or swept away by floodwaters, many
were damaged, and numerous roads closed, along with power, gas and
supply outages to tens of thousands of people. The cost of damage
from the floods has well exceeded $100 million. Further flood-producing
rainfall occurred in parts of Northland, Auckland, Coromandel, Waikato,
Bay of Plenty, King Country, and Taranaki on the 28th.
Rainfall was also above average in most other
of New Zealand. Many locations experienced 7 to 10 more wet days
average for the time of year, some more. Unusually, soil moisture
exist in some North Island areas, and the west of the South Island.
soil moisture deficits remain high in parts of central Marlborough,
and Otago. Temperatures were below normal. Sunshine totals were well
normal throughout the south and west of the North Island.
The highest February 2004 temperature was
recorded at Alexandra on the 2nd.
The lowest temperature for the month was
recorded at Manapouri on the 26th.
High rainfall events were frequent during the
affecting Northland, Auckland, Bay of Plenty, Waikato, Coromandel, East
Cape, southern Hawke’s Bay, Wairarapa, King Country, Tongariro/
Taranaki, Wanganui, Manawatu, Wellington/Lower Hutt, the Marlborough
Westland, and Fiordland. Most northern and western regions experienced
at least two high rainfall events during the month. The most
of these produced widespread rainfall totalling 65–150 mm in the 24
to 9 am on the 16th in many population centres (with very
higher totals in the high-country catchments) throughout the southwest
North Island, from Taranaki to Wellington, as well as in southern
Bay, Wairarapa, and the Marlborough Sounds, with further high rainfall
in Wanganui and Taranaki on the 18th. The same weather event
also produced storm-force southerlies and high seas, which buffeted
of the North Island, from the afternoon of the 15th into the
morning of the 16th. Ferry sailings were cancelled and
delays occurred at Wellington airport and other airports due to high
There were power cuts and fallen trees in some areas.
Gales (from the northwest) affected the
region on the 21st, and around Dunedin (from the southwest)
on the 24th.
A depression from the Tasman Sea and the
of tropical cyclone Ivy produced rainfall, in excess of 100 mm in
of Northland, Auckland, Coromandel, Waikato, Bay of Plenty, King
and Taranaki on the 28th with houses flooded in Turangi as
Tongariro River overflowed its banks. Storm force northeasterlies
to 120 km/h at Cape Reinga, with gales also affecting Auckland.
Of the four main centres, Dunedin was the driest.
was very wet in Auckland, Wellington and Christchurch. Temperatures
below average in all four centres. Sunshine hours were below normal in
Auckland and Wellington, and near normal in Christchurch, and Dunedin.
Rainfall was 400–600 percent (four to six
average February totals in much of the south and west of the North
Island from Waikato to Wellington, including Wairarapa, and 200–300
percent of average in most other North Island regions, as well as
north Westland, Marlborough and Nelson. Totals were also above
over much of the South Island.
Mean temperatures were as much as 2.5°C below
in the Southern Lakes, Central Otago, and inland Canterbury, and below
normal in most other regions. However, Hawke’s Bay temperatures were
average. The February national average temperature of 16.1°C was
Sunshine totals were extremely low throughout the
and west of the North Island, and below normal in most other regions.
sunshine was near normal in Canterbury and coastal Otago.
Acknowledgement of NIWA as the source is
© Copyright 2004 by NIWA