Brazil: Adverse weather forecast across southern regions through at least May 2

Severe weather is forecast across parts of southern Brazil through at least May 2. A stationary cold front over the region will bring heavy rainfall and strong winds to affected areas. Rainfall totals of more than 10 cm (4 inches) are possible across parts of the region. Sustained heavy rainfall may trigger flooding in low-lying areas and landslides on unstable slopes.

As of April 30, Brazil's National Institute of Meteorology (INMET) has issued red heavy rainfall warnings (the highest level on a three-tier scale) across central, eastern, southern, and western Rio Grande do Sul State and far southeastern Santa Catarina State. Orange heavy rainfall warnings are in place for parts of northern and southeastern Rio Grande do Sul and southeastern Santa Catarina and yellow heavy rainfall warnings for far northern Rio Grande do Sul and southern Santa Catarina. Officials could update and possibly extend the coverage of the relevant weather alerts over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. In developed areas with easily overwhelmed stormwater drainage systems, additional urban flooding is also possible. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides remain possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil. Power outages and disruptions to telecommunications services are likely where significant flooding, landslides, or strong winds impact utility networks.

Floodwaters and debris flows could render some bridges, rail networks, or roadways impassable, impacting overland travel in affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger intermittent flight delays and cancellations at airports in the affected regions, though these are unlikely to be severe or prolonged. Authorities may temporarily suspend port operations or close beach fronts along the Atlantic coast if strong winds trigger hazardous sea conditions. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and track inundation. Localized business disruptions may occur in low-lying areas.