In the height of the rains from March through May, the trails become unpleasantly muddy.
"So if the rains don't come when needed, you don't lose an entire crop, " Ehrhart said.
At the beginning of the rains, both food crops and leguminous trees are planted.
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Lena has heard the warnings and knows her tent could be swept away by the rains.
On average nine children were dying in the camp every day before the rains.
The authorities here say that the rains are expected to die down on Thursday.
Officials worried that if the rains return, they could bring more floods if reservoirs burst.
Now that the rains have set in, the 250 mile journey takes a week and a half.
The rains also flooded the country's largest refinery, causing a fire that took hours to put out.
If the rains return within a few months, the main crop in October-November will not be badly affected.
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The rains are already starting to fall, and an anxious night lies ahead.
The rains are expected to get worse next month, bringing even more misery.
Mr Mugabe's stated aim is to resettle 500, 000 families about a sixth of the population before the rains start in November.
Even in Maputo city, poor drainage and illegal building meant that the rains caused mudslides that destroyed houses and blocked roads.
All they offer is a floor to sleep on and shelter from the rains that pound Uganda this time of year.
The rains that fell were cold, persistent, and slow to dry up.
Thousands of people have been forced from their homes by the rains.
Prudence is not always a virtue: the instinct to save for a rainy day seems only to harden when the rains set in.
But Russia's Tursunov was unable to build on that victory, going down 4-6 6-1 6-3 to talented Brazilian Thomaz Bellucci before the rains intervened.
In southern Africa, too, the rains have been heavier than usual.
The rains this season have not been as heavy nor as constant as last year, when they were seven times heavier than average, according to meteorologists.
In Buenos Aires, where the rains had been at their worst overnight Monday to Tuesday, the floods have begun to recede and residents have started the clean-up.
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In addition, they are habituating elephants to charge vehicles, which they will continue to do once they leave the national park with the beginning of the rains.
Parts of northern India, including the capital Delhi, have been in the grip of intense heat and there have been severe water shortages as the rains are late.
Waves of zebras arrive first, mowing through the tall, coarse grass stems that shot up during the rains and exposing the green leafy grasses preferred by the wildebeests following behind them.
Conditions are favorable for the rains to reach more parts of southern India in the next two days and the western coast within a week, the weather department said.
The rains usually arrive over the southern state of Kerala by the end of May or the first week of June, and gradually cover the entire country by July.
Some of the worst-affected regions are deceptively green: the rains fell too little and too late for crops, but just enough to entice grass shoots out of the soil.
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With the rains over, the rebels, together with their outside supporters, are moving rapidly westwards, taking one town with a short sharp attack, and then moving on to the next.
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