Johannesburg, 4 November 2010 (IRIN) - Dominicano Mulenga, national coordinator of Zambia's Disaster Management and Mitigation Unit, goes through his to-do list as the rainy season sets in: Industrial pumps to suck water out of the roads serviced. Tick. Enough stocks of tents and mosquito nets. Tick. Mobile phones delivered to communities living along the upper catchment areas of the River Zambezi. Check.

"We do not want a repeat of the situation from last year, when 1,000 people were displaced in Lusaka [the Zambian capital] alone because of poor drainage," said Mulenga.

Mulenga is one of several officials in Southern African gearing up for the rainy season which normally goes on until the end of March 2011. But this year, with the La Niña influence, the region is bracing for a wetter than usual season.

The US Agency for International Development's Famine Early Warning Systems Network (FEWS-NET) has warned of possible flooding along some of the major rivers such the Zambezi, which flows through seven southern African countries, and more cyclones in the Indian Ocean, which would affect Mozambique and Madagascar.

Heavy rain brought on by the lingering effect of La Niña in 2009 caused the worst floods to hit Namibia in four decades, and extensive damage in Zambia estimated at several million US dollars.

La Niña is characterized by unusually cold ocean temperatures in the eastern equatorial Pacific Ocean, whereas El Niño is associated with warmer than normal water temperatures, according to the US government's National Oceanic and Atmospheric Administration (NOAA).

La Niña strengthens

"Both of these climate phenomena, which typically occur every 2-5 years, influence weather patterns throughout the world and often lead to extreme weather events," said NOAA, which has indicated in its latest update that this year's La Niña has strengthened further.

The phenomena are called El Niño/La Niña-Southern Oscillation, or ENSO.

La Niña is usually associated with more rain in Southern Africa, but it is very difficult to predict the impact, as this could vary within the African region and from one La Niña event to another, say scientists such as Cobus Olivier with the prediction research section of the South African Weather Service.

But based on the latest update on ENSO, there is a strong chance that many parts of the region could be in for above-normal rains, Olivier said.

Southern Zambia, Malawi and Madagascar, central and southern Mozambique and parts of Namibia, Botswana, Zimbabwe and South Africa are in for more rain than usual.

"But we are also expecting dry spells in some parts of Malawi," said James Chiusiwa, coordinator of Malawi's Department of Disaster Management Affairs. His department has begun holding contingency planning meetings with different government and aid agencies. "We are trying to ensure we have enough stocks of emergency relief items."

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