El Niño update
The following is based on a statement prepared for the United Nations Interagency Task Force on Natural Disaster Reduction as a collaborative effort between the World Meteorological Organization and the International Research Institute for Climate Prediction (IRI), drawing also on contributions from regional climate authorities including NIWA.
Climate Update 32 - February 2002
Outlook and outcome – November 2001 to January 2002
Normal to above normal rainfall was predicted in the north of both islands and near normal elsewhere. Rainfall was above normal in most regions, with near normal totals in the southwest South Island.
Temperatures were expected to be above normal over northern and western North Island regions, and nearer normal elsewhere.
Climate Update is a summary each month of New Zealand's climate, including soil moisture and river flows.
February 2002 – Number 32
January’s climate: Storms and highest January rainfalls on record in Canterbury.
January’s river flows: High January flows in the eastern South Island.
Soil moisture levels: Above average soil moisture levels from Auckland to Christchurch.
Three month outlook: Some relief from the wet conditions of the last two months with normal or below normal rainfall expected.
Checkpoint: How well are we doing with our predictions?
Backgrounder: Update on
New Zealand Climate in January 2002
A wild start to 2002
Thunderstorms, lightning, torrential rain and localised flooding marked the start of the year. Hokitika recorded 481 lightning flashes on 2 January, and 937 flashes over the first four days of the year. A tornado uprooted trees on the Levin golf course on 4 January. Christchurch had hail up to 7.5 cm deep on 5 January. Westport was flooded on 3 January when up to 38 mm of rain fell in an hour. Wellington city centre was flooded on 10 January when 40 mm fell in 30 minutes.
The outlook for February to April 2002
Recent changes in the Pacific mean an El Niño "alert" is in place, but it is too early in the year for a confident El Niño prediction to be made (see page 4).
New Zealand River Flows in January 2002
High January flows in the eastern South Island
January flows were near average for North Island rivers and for rivers draining the Southern Alps. Record high January average flows were recorded in parts of Marlborough, and in the Canterbury foothills and north Otago. Scouring of the rail track beside the Rangitata River derailed a freight train on 4 January.
Rivers flowed at above normal levels in Nelson. Conversely, many Southland rivers had lower flows than usual.
Soil moisture on 31 January
Above average soil moisture levels from Auckland to Christchurch
High January rainfalls lifted soil moisture levels in many areas from Auckland city south to the northern half of the South Island.
Northland, Otago, and Southland total soil moisture storage was mostly lower than average at the end of the month.