Cyclone Catarina

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Cyclone Catarina

Category 2 cyclone (SSHS)

Catarina, as seen from the International Space Station.

Formed

March 24, 2004

Dissipated

March 28, 2004

Highest
winds

155 km/h (100 mph) (1-minute sustained)

Lowest pressure

Unknown

Fatalities

3–10 direct

Damage

$350 million (2004 USD)
$374 million (2006 USD)

Areas
affected

Santa Catarina and Rio Grande do Sul, Brazil

Part of the
2003-04 Southern Hemisphere tropical cyclone season

Cyclone Catarina was an extremely rare South Atlantic tropical cyclone. Catarina hit southeastern Brazil in late March of 2004, and though not the first southern Atlantic tropical cyclone, it was the first positively identified hurricane-strength system in the basin. The storm killed at least 3 people and caused an estimated $350 million (2004 US dollars) in damages.

1 Storm history
2 Naming
3 Rare formation
4 Impact
5 See also
6 References
7 External links

Storm path

On March 12, a cold-core stationary upper-level trough became established offshore southern Brazil. A disturbance formed along it on the 19th, and moved east-southeastward until the 22nd, when a ridge to its southeast kept it stationary. With exceptionally unusual favorable upper level winds and above average if marginally warm water temperatures from 24 to 26 °C (75 to 79 °F), it gradually developed, resembling a subtropical storm by the 24th. Located 630 statute miles (1010 km) east-southeast of Florianópolis, it headed slowly westward, and appeared to become a tropical storm on the 25th.

A compact storm, it continued westward while steadily intensifying, reaching hurricane strength on the 26th. A Brazilian newspaper indicated a "Furacão (hurricane) threatening Santa Catarina (the Brazilian state)". Partly because of this, the storm had unofficially been named Catarina due to the headline. Catarina continued to encounter favorable conditions, and reached a peak of 100 mph (160 km/h) estimated sustained winds on the 28th,^[1] which made the storm a Category 2 hurricane on the Saffir-Simpson hurricane scale. Gusts peaked at around 110 mph (180 km/h). The cyclone made landfall at that intensity, hitting just north of the town of Torres (northeast of the extreme southern Brazilian state of Rio Grande do Sul). Catarina rapidly dissipated over land in the normal manner of a tropical cyclone.

Catarina approaching the Brazilian coastline on March 27, 2004.

Brazilian meteorologists named the storm Catarina for its proximity to (and eventual landfall at) the state of Santa Catarina, although government forecasters initially denied that the storm, which clearly had an open eye and various other tropical morphologies, was a hurricane at all. More than a year after the storm made landfall, Brazilian meteorologists finally classified the storm as a tropical cyclone.^[2]

North American forecasters, however, surprised as they were, considered this a hurricane immediately upon the satellite-derived evidence. Since it had clear eyewall structure bounded by deep convective central dense overcast, well-defined spiral outer bands and outflow structure, warm water temperatures of 79°F (26°C), little shear, a warm core low, and overall tropical characteristics, it was considered a hurricane by the National Hurricane Center in the United States.^[3]

Though it is most commonly known as Catarina, all names for this storm are "unofficial", in that no World Meteorological Organization-affiliated meteorological agency that monitors hurricanes named it. (Tropical cyclone names are predetermined by an international committee of the World Meteorological Organization.)^[4] It has also been unofficially called "Aldonça"^[5], and the advisory names for it were "01T-ALPHA" from the United Kingdom's Met Office, and "50L-NONAME" from the United States' National Hurricane Center, which keeps it well outside normal designation, which start at 1L for named storms and use 90L to 99L for possible storms.

There is also no official naming convention for the meteorological term of tropical cyclones with winds of at least 74 mph (119 km/h) (i.e. hurricane, typhoon, cyclone) in the South Atlantic basin; however, because it was in the Southern Hemisphere, it is typically considered Cyclone Catarina, the predominant term for Southern Hemisphere tropical cyclones.

Typically, tropical cyclones don't form in the South Atlantic Ocean, due to strong upper level shear, cool water temperatures, and the lack of a convergence zone of convection. Occasionally though, as seen in 1991 and early 2004, conditions can become slightly more favorable. For Catarina, it was a combination of climatic and atmospheric anomalies. Water temperatures on Catarina's path ranged from 24 to 25 degrees Celsius, slightly less than the 26.5 °C temperature of a normal tropical cyclone, but sufficient for a storm of baroclinic origin.

Up to that point, no tropical cyclone had been observed to reach hurricane strength on the South Atlantic Ocean via satellite imagery, which dates back to the mid 1970s.^[6] While Catarina formed in an unusual area, whether it is related to global warming or another type of global climatic change is still up for debate. The Brazilian Society of Meteorology attributed it to "climatic changes and atmospheric anomalies,"^[2], while other researchers have indicated that it could be the result of the Southern Annular Mode or other seasonal variations in weather within the Southern Hemisphere, again linked to global changes in climate.^[7] However, more research in the area is still needed to make a conclusion.^[7]

Location of the Santa Catarina state in Brazil.

Like normal tropical cyclones, Catarina brought heavy flooding with it. Because Brazilian government meteorologists refused to acknowledge the tropical characteristics and potency of Catarina, many people did not take shelter, increasing the threat for damage. In the end, the storm damaged around 40,000 homes and destroyed 1500; 85% of the banana crop and 40% of the rice crop were lost; total damages were estimated at $350 million (2004 USD, $359.45 million 2005 USD). It also killed at least three and injured at least 75. ^[8]

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.^[9]. Near the Mampituba River, a house was blown about 50 meters (165 ft) upstream, literally landing in another state: it originally was built in the Torres municipality of Rio Grande do Sul, yet it ended up in Passo de Torres, within Santa Catarina State. On rural areas, the corn, banana and rice fields were the ones that received the most damage, although rice farmers were able to partially recoup their loses, as they had harvested before Catarina made landfall. ^[9]

Overall, almost 36,000 residences were damaged as a result of Catarina's onslaught; of those, 993 collapsed completely. The commercial sector fared slightly better, as only 2,274 buildings were damaged, and 472 collapsed. Finally, 397 public buildings were damaged, and three were destroyed. These account for 26% of the total buildings in the region, and property damage of $25.6 million (2004 USD). Four fifths of the damaged houses had some sort of roof failure or collapse. Most of the damage was blamed on the low quality of the constructions; brick residences typically lacked plaster, beams or columns, for example. The areas affected the most were those habitated by low-income families, usually with family salaries of less than $400 USD.^[9]