South Africa: Why April Rainfall Is Key to Stave Off Cape Town's Day Zero

In three weeks' time experts will be able to say with some certainty whether Cape Town is likely to get enough rain this year to avoid a Day Zero scenario in 2019.

After three dry years and months of severe water restrictions, everyone in the drought-stricken area wants to know whether we will get the above-average rains we need to fill the dams sufficiently to break the drought and see us through next summer.

Now scientists Peter Johnston and Piotr Wolski at UCT's Climate System Analysis Group have worked out that April is key to answering that question.

After analysing rainfall figures from the Western Cape dam catchment areas from 1930 to 2017, they found that if rainfall recorded by the end of April is above normal, it is likely that we will have above normal rainfall for the rest of the year.

"If the cumulative total is above normal by the end of April we can say there is a 70% chance of it being wetter than normal by the end of the year," Johnston said.

If the rainfall by the end of April is average or below average, it does not throw light on the rest of the year's rainfall - but May and July have some answers in that regard.

The researchers have found that if by the end of May we have had below average rainfall, we are likely to have below average rainfall for the rest of the year.

"And if rainfall by the end of May is normal, there is an equal chance of going either way."

If rainfall figures at the end of July are normal, it is likely we will have normal rainfall for the rest of the year.

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Source: AllAfrica