Brazil: Flood-related disruptions persist in southern regions as of May 22 /update 8

Flood-related disruptions are ongoing across much of Rio Grande do Sul State as of May 22. Heavy rainfall since late April has triggered widespread flooding and associated damage and casualties, affecting more than 2 million people across 467 of the state's 497 municipalities. As of late May 21, authorities have reported 161 flood-related fatalities and 806 others injured, while another 82 people are missing. Over 580,000 people have been displaced, of which over 70,000 are being housed in emergency shelters. The state capital Porto Alegre is amongst the worst-affected locations. As of May 22, operations remain suspended at Salgado Filho International Airport (POA) until further notice due to flooding; airlines have announced that commercial flights will begin operating at the Canoas Air Base, located around 21 km (13 miles) north of Porto Alegre, from late May due to the ongoing closure at POA. Public transport, including in Porto Alegre, is severely disrupted. Flood waters have cut off towns across the region, as hundreds of roads have been blocked by flooding across Rio Grande do Sul. Power outages are impacting multiple locations. The governor of Rio Grande do Sul has declared a state of calamity.

Water levels remain at critical levels in most river basins across the state. Further adverse weather is forecast over the coming days, likely exacerbating the ongoing flood situation. As of May 22, the National Institute of Meteorology has issued orange heavy rainfall warnings (the middle level on a three-tier scale) across southern and western parts of Rio Grande do Sul and yellow heavy rain warnings for south-central regions.

In recent days, flooding has also been causing disruptions across parts of Santa Catarina State. Heavy rainfall has caused rivers to overflow and resultant floods have affected 24 municipalities across the state. More than 650 people have been displaced and a state of public calamity has been declared in at least eight municipalities. Many roads have been blocked due to flooding and landslides, leaving some communities isolated.

Further sustained heavy rainfall could trigger additional flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. 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 rain has saturated the soil. Power outages and disruptions to telecommunications services will likely occur 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 further trigger intermittent flight delays and cancellations at regional airports. Authorities will likely 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 probable in areas with heavy rainfall and track inundation. Localized business disruptions will likely occur in low-lying areas.

Stagnant pools of water during and after flooding increase insect- and waterborne diseases, such as dengue fever, cholera, and malaria. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a severe health threat.