The Guaiba river reached a record level of 5.33 metres on Sunday morning, surpassing levels seen during a historic 1941 deluge, when the river reached 4.76 metres. The downpour started on Monday, 29 April. In some areas, such as valleys, mountain slopes and cities, more than 300 millimetres of rain fell in less than a week, according to Brazil’s National Institute of Meteorology, known by the Portuguese acronym INMET. The heavy rains were the fourth such environmental disaster in the state in a year, following floods in July, September and November 2023 that killed 75 people. Weather across South America is affected by the climate phenomenon El Niño, a periodic, naturally occurring event that warms surface waters in the Equatorial Pacific region. In Brazil, El Niño has historically caused droughts in the north and intense rainfall in the south.
