Catarina made landfall in Southern Brazil at peak intensity, with the equivalent of Category 1 hurricane-force sustained winds, on 28 March 2004.

The disturbance was in an unusually favorable environment with a slightly below-average wind shear and above-average sea surface temperatures.

Abnormally favorable conditions persisted, resulting in Catarina intensifying further, and it would peak with 1-minute sustained winds of 137 km/h (85 mph) on 28 March.

Catarina was the first tropical cyclone to make landfall in Brazil since the beginning of reliable records; hence, the infrastructure and population were not specifically prepared for it, which led to severe damage.

Located 630 nautical miles (1,165 km; 725 mi) east-southeast of Florianópolis, it headed slowly westward, and appeared to become a tropical storm on 25 March.

Soon afterward, the hurricane made landfall on the southern coast of Santa Catarina and northeastern Rio Grande do Sul, with winds up to 195 km/h (121 mph) overnight.

After making landfall, Catarina rapidly weakened over land, in the normal manner of a tropical cyclone, dissipating later that day.

[3] Typically, tropical cyclones do not form in the South Atlantic Ocean, due to strong upper-level shear, cool water temperatures, and the lack of a convergence zone of convection.

[4] Catarina remains the only hurricane strength tropical cyclone ever observed in the South Atlantic Ocean (reliable continuous and relatively comprehensive records only began with the satellite era beginning about 1970).

[11] At Passo de Torres, many shipyards were destroyed, as they were not designed to withstand the pressure differentials caused by Catarina's winds; widespread roof damage was reported at this municipality as well.

Most of the damage was blamed on the low quality of the construction; brick residences typically lacked plaster, beams, or columns, for example.

[12] Many studies were published out to measure Complex post-traumatic stress disorder, its symptoms and depression, focusing on cognition and biological indicators.

[clarification needed] The impact on children is considered particularly difficult to analyze because random assignments and double-blind procedures may not be possible or ethical for them, and therefore studies are usually limited to testing causal hypotheses.

[13] A 2021 study found that the hurricane adversely affected children in utero, leading to reduced birth weight and increases in fetal deaths, possibly due to maternal stress.