South America Calling

More Rain, More Flooding for Southern Brazil

John Baranick
By  John Baranick , DTN Meteorologist
More heavy rain is coming to the state of Rio Grande do Sul in southern Brazil, where over 100 millimeters (4 inches), is forecast over the next 10 days. (DTN graphic)

A stalled frontal boundary in the southern Brazil state of Rio Grande do Sul created intense flooding in late April and early May. But the weather since then has continued to aggravate the flooding and created a real humanitarian crisis.

According to this report from ABC News,…, 149 people have been confirmed dead, another 124 are currently missing, and over 600,000 people have been displaced. Over these last two weeks, we have seen image after image of incredible flood damage all over social and digital media as rains have continued to fall in the region after the front responsible for the initial flooding finally left on May 4. Another front produced rainfall around 100 millimeters (about 4 inches) last weekend. In total, some areas have seen more than a meter (39.4 inches) of rainfall over the last 30 days, which has been absolutely devastating. And more is coming.

Another front is loading up to produce more rain May 16-17 where an additional 30 to 75 millimeters (1.2-3 inches) is forecast across the northern end of the state. That front does work a little farther north with some needed showers in the states of Parana and Mato Grosso do Sul this weekend, but the continued flooding along the state's river systems should continue to get a lot of attention.

And the threat isn't over there either. Another front looks to develop over the state of Rio Grande do Sul on May 21 with heavy rain through May 23 before that front also pushes north. Model forecasts of yet another 50 to 100 millimeters (about 2 to 4 inches) are common across the state. The most recent run of the European ECMWF model has locally heavier amounts across the northern end of the state again. Above-normal precipitation is forecast to last through June.

Heavy rains have not only occurred in that state, though it has seen the worst of it. The state of Santa Catarina to its north and northeastern Argentina and southeastern Paraguay to its west have also come under some extreme rainfall amounts. Over the last 30 days, estimates of 300 to 500 millimeters (12-20 inches) of rain have fallen in many of these areas as well, creating flooding concerns of their own.

Brazilian President Lula has announced National Civilian Defense resources to help with the rebuilding and rescue efforts, but those efforts may take months based on the continued heavy rainfall pattern in the region.

The continued barrage in the state has not only led to a loss of life and personal property, but also crop and infrastructure damage. Major disruptions to Porto Alegre, the state's main access to the Atlantic Ocean, are expected to continue. Furthermore, rainfall from the northern end of the state eventually pours into the Uruguay River, bringing disruptions up and down this river system's ports as well.

As of May 12, CONAB estimates 16% of its rice, 14% of its corn, and 21% of its soybean crops are yet to be harvested. Major losses to this portion of the crop are likely. To go along with that, planting of winter grains will be pushed far into the future. Winter wheat planting has yet to begin, but that is typical. Winter sowing usually starts by the end of May, but that will likely take more time this year and planted area will likely be lower than normal.


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