GENEVA - The United Nations weather agency predicts the phenomenon known as La Nina is poised to last through the end of this year, a mysterious “triple dip” – the first this century – caused by three straight years of its effect on climate patterns such as drought and flooding worldwide.

The World Meteorological Organization (WMO) on Wednesday said La Nina conditions, which involve a large-scale cooling of ocean surface temperatures, have strengthened in the eastern and central equatorial Pacific with an increase in trade winds in recent weeks.

Taalas said the drought in the Horn of Africa and southern South America “bears the hallmarks of La Nina.” “The new La Nina update unfortunately confirms regional climate projections that the devastating drought in the Horn of Africa will worsen and affect millions of people,” he said.

That drought is set to worsen with a fifth consecutive failed rainy season, the WMO projected on Friday, fearing an unprecedented humanitarian catastrophe. Ethiopia, Kenya and Somalia are already going through their worst drought for 40 years.