Cyclone Giovanna

Intense Tropical Cyclone Giovanna

Intense tropical cyclone (SWIO scale)
Category 4 (Saffir–Simpson scale)
Intense Tropical Cyclone Giovanna approaching Madagascar on February 13, 2012
Formed	February 7, 2012
Dissipated	February 24, 2012
(Extratropical after February 22, 2012)
Highest winds	10-minute sustained: 195 km/h (120 mph) 1-minute sustained: 230 km/h (145 mph)
Lowest pressure	935 hPa (mbar); 27.61 inHg
Fatalities	At least 35
Areas affected	La Réunion, Mauritius, Madagascar
Part of the 2011–12 South-West Indian Ocean cyclone season

Intense Tropical Cyclone Giovanna was a powerful tropical cyclone that affected Madagascar. Giovanna was the ninth tropical depression, seventh named storm and third tropical cyclone of the 2011–12 South-West Indian Ocean cyclone season. Giovanna is still blamed for 33 deaths along the Madagascar coast, and it is the first intense tropical cyclone to impact Madagascar, since Cyclone Bingiza in February 2011.

Cyclone Giovanna developed from a tropical wave over the Indian Ocean heading to the southwest on February 7. The tropical disturbance soon developed into Tropical Depression 09 on February 9. That same day the JTWC upgraded the system into 12S. The storm intensified into a moderate tropical storm and was given the name Giovanna. On February 10, Giovanna continued to strengthen into a severe tropical storm. Later the same day, Giovanna went through a rapid intensification and became an intense tropical cyclone, due to favorable conditions and great convection wrapping around the system.

Soon, Giovanna began an eyewall replacement cycle and weakened into a tropical cyclone on February 11 due to high wind shear surrounding the system. However, the wind shear surrounding Giovanna soon weakened and Giovanna was able to strengthen back into an intense tropical cyclone, and finished the eyewall replacement cycle resulting with a new, larger eye at 50 kilometers across.

At about 2200 UTC February 13, Giovanna made landfall on Andovoranto, Madagascar. Giovanna then weakened into an overland tropical depression on February 14. Early on February 15 Giovanna moved back out into open water. The storm soon drifted southwards, on February 18, as Giovanna moved eastwards, along the bottom of Madagascar, the storm was steered into warmer waters, by a strong Anticyclone located south of Giovanna where it strengthened into a Category 2 tropical cyclone again, and developed a small eye. However the eye soon underwent an eyewall replacement cycle, and developed double eye walls due to moderate wind shear. On February 20, Giovanna entered an area of strong vertical wind shear which quickly weakened the system into a tropical depression and displaced the system's convection to south of the system's exposed circulation center. This caused Giovanna to dissipate into a remnant low, with the low level circulation center totally exposed by the next day. The exposed remnants were soon pushed further northwest the next day, due to the Fujiwhara interaction between the much stronger system in the east, Moderate Tropical Storm Hilwa, before Giovanna's remnants finally dissipated east of Madagascar, late on February 21.