Over the past three weeks, torrential wet season
rains have fallen throughout parts of south-central Africa, including Zaire,
Tanzania, Mozambique, Malawi, Madagascar and adjacent waters. This image
shows a rainfall accumulation map obtained using NASA's Tropical Rainfall
Measurement Mission (TRMM) satellite, combined with data from other rain
measuring satellites. Three weeks of rain accumulation are shown, beginning
on January 1, 2003. Rainfall accumulations approach two feet in some locations,
leading to serious flooding and the displacement of many people from their
homes. Many areas of the tropics endure a perpetual "drought-flood
seesaw" over the years and this region of Africa is no exception.
These rains, while helping to break a multiple year drought, have also
seriously damaged this season's crops.
The heavy rains are an extreme manifestation
of the annual pattern of summer rainfall across the southern hemisphere,
known as the Intertropical Convergence Zone (ITCZ). Over south central
Africa, warm and humid air flowing off the Arabian Sea clashes with the
hot, dry Harmattan (desert wind) blowing southward off northern Africa.
Violent thunderstorm rains erupt within this atmospheric battle zone. The
heavy rains shown in the image over Tanzania and neighboring countries
were enhanced by mountainous terrain. The mountains force moisture-laden
air from the ocean to ascend, producing more rain within clouds, then concentrate
rain runoff into narrow valleys.
Other extreme rainfall events from the past
year can be seen on the TRMM website (trmm.gsfc.nasa.gov).
Image courtesy of Hal Pierce, NASA Goddard
Space Flight Center.
more information on Flooding in South Eastern Africa please see the ReliefWeb
Natural Disaster Homepage