MercoPress. South Atlantic News Agency

Black rain forecast for southern Brazil and northern Uruguay

The sky color in the Brazilian State of Rio Grande do Sul has changed due to numerous fires in the region

Brazilian Meteorological researchers Metsul have issued a black rain warning for the southern part of the region's largest country, which could also be affecting northern Uruguay Thursday -Cerro Largo, Rivera, and parts of Rocha- given a cold front clashing with a smoke plume from the large number of fires in the region, it was explained.

Metsul said a large amount of soot is in the atmosphere, with a column of smoke originating in Bolivia and the Amazon region, extending towards southern Brazil.

A cold front is expected to cause rain in almost the entire Brazilian State of Rio Grande do Sul where the sky's color has experienced unusual changes as a result of the smoke.

“With the huge amount of smoke present in the atmosphere and the prospect of instability between today and tomorrow, the occurrence of black rain with soot precipitation in different cities in Rio Grande do Sul cannot be ruled out,” Metsul said. The “Amazon registers a record number of fires for the month of August in 14 years,” the agency also noted.

Similar forecasts have been issued for parts of the States of Paraná and Santa Catarina.

Soot is a particulate material stemming from the incomplete combustion of organic materials, such as fossil fuels (coal, oil) and biomass (wood, agricultural waste). When these materials do not burn completely, instead of turning entirely into carbon dioxide and water vapor, they produce fine black particles with diameters in the nanometer to micrometer range, which allows them to remain suspended in the air for long periods and travel great distances.

Soot and black rain are closely related. Black rain is a phenomenon that occurs when soot and other contaminating particles present in the atmosphere mix with moisture and precipitate in the form of rain.