This is a good article. Follow the link for more information.

Cyclone Gamede

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Intense Tropical Cyclone Gamede
Intense tropical cyclone (SWIO scale)
Category 3 tropical cyclone (SSHWS)
Cyclone Gamede 25 February 2007 0950Z.jpg
Cyclone Gamede on February 25
FormedFebruary 20, 2007 (2007-02-20)
DissipatedMarch 6, 2007 (2007-03-07)
(Extratropical after March 2)
Highest winds10-minute sustained: 165 km/h (105 mph)
1-minute sustained: 195 km/h (120 mph)
Gusts: 230 km/h (145 mph)
Lowest pressure935 hPa (mbar); 27.61 inHg
Fatalities4 direct
Damage$26 million (2007 USD)
Areas affectedMascarene Islands
Part of the 2006–07 South-West Indian Ocean cyclone season

Cyclone Gamede was among the wettest tropical cyclones on record, dropping more than 5.5 m (18 ft) of rain in a nine-day period on Réunion island in the southwest Indian Ocean. Only Cyclone Hyacinthe has a higher recorded rainfall total. The seventh named storm of the 2006–07 South-West Indian Ocean cyclone season, Gamede formed south of Diego Garcia on February 19 as a tropical disturbance. It tracked generally westward and steadily intensified, reaching tropical cyclone status on February 23. For two days, Gamede stalled northwest of the Mascarene Islands as an intense tropical cyclone, during which it reached 10 minute maximum sustained winds of winds of 165 km/h (105 mph), according to the Météo-France meteorological office in Réunion.[nb 1] The American-based Joint Typhoon Warning Center (JTWC)[nb 2] estimated peak 1 minute winds of 195 km/h (120 mph), equivalent to a Category 3 on the Saffir-Simpson scale. For four days, Gamede remained within 400 km (250 mi) of Réunion before accelerating southward. On March 2, Gamede transitioned into an extratropical cyclone to the southeast of Madagascar. The MFR tracked the storm for four more days.

Gamede broke rainfall records set by Cyclone Hyacinthe 27 years earlier for the accumulated totals between three and nine days, though Hyacynthe still dropped more rainfall overall. The rainfall caused moderate damage in Réunion, and in the southern portion of the island a bridge collapsed due to the storm. Two people each were killed on Mauritius and Réunion. The name Gamede was submitted to the World Meteorological Organization by South Africa.[2]

Meteorological history[edit]

Map plotting the track and the intensity of the storm, according to the Saffir–Simpson scale

The intertropical convergence zone was active across the Indian Ocean in the middle of February 2007, which spawned a low pressure area southeast of Diego Garcia on February 18.[3] The system developed convection, or thunderstorms, over a weak, but well-defined low-level circulation.[4] The MFR first began tracking the system as a tropical disturbance on February 19.[5] An anticyclone over the nascent system provided weak wind shear and outflow to the north and east, both favorable conditions for development. With a subtropical ridge to its south, the disturbance tracked generally westward for the first few days of its duration.[4] By late on February 20, the system had organized enough for the MFR to upgrade the disturbance to a tropical depression,[5] and for the JTWC to issue a tropical cyclone formation alert.[6] On the next day, the MFR upgraded the depression to Moderate Tropical Storm Gamede, and the JTWC began issuing advisories on the storm as Tropical Cyclone 15S. At that time, the storm was located about 785 km (490 mi) south-southwest of Diego Garcia, or about 995 km (620 mi) northeast of Rodrigues.[3][6]

As Gamede continued to intensify, its track shifted to the west-southwest.[4] On February 22, the MFR upgraded the system to a severe tropical storm, and the JTWC upgraded Gamede to the equivalent of a minimal hurricane.[5] An eye became evident on satellite imagery, a sign of the storm's development.[7] The MFR upgraded Gamede to tropical cyclone status on February 23, noting that the system was "very broad".[8] Soon after, the cyclone moved over St. Brandon, one of the Outer Islands of Mauritius; the island recorded a minimum barometric pressure of 955 mbar (28.2 inHg), and estimated the eyewall diameter at 50 km (30 mi).[3] On February 24, Gamede passed north of Mauritius and Réunion, approaching within 300 km (190 mi) of the latter island. The storm later slowed and stalled, trapped between the subtropical ridge to the south and a ridge to its northeast. For over 90 hours, the cyclone remained within 400 km (250 mi) of Réunion, resulting in torrential rainfall in the island's mountainous region. During this time, Gamede executed a small loop, and the cyclone attained its peak intensity. The MFR estimated peak 10 minute winds of 165 km/h (105 mph) late on February 25. At the same time, the JTWC estimated peak 1 minute winds of 195 km/h (120 mph).[5][4]

Comparison of previous world record and rainfall
from Cyclone Gamede on Réunion
Bold indicates current world record
Duration
(hours)
Storm name
and year
Record prior
to Gamede
Gamede total +/-
(in mm)
mm in mm in
24 Denise (1966)[9] 1825 71.8 1625 64.0 -200
48 Unnamed (1958) 2467 97.1 2463 97.0 -4
72 Hyacinthe (1980) 3240 127.6 3929 154.6 +689
96 Hyacinthe (1980) 3551 139.8 4869 191.7 +1318
Total Hyacinthe (1980) 5678 223.5 5512 217.0 -166

While remaining nearly stationary northwest of the Mascarene Islands, Gamede lost some of its deep convection due to upwelling, the process in which a stationary storm causes the water temperatures to decrease by bringing the cooler, deeper waters to the surface.[4] Early forecasts suggested the possibility that the cyclone would turn westward and strike Madagascar near Toamasina.[10] Instead, a passing trough steered the system to the south-southwest. On February 27, Gamede passed west of Réunion, about halfway between the island and Madagascar.[4] On the next day, the convection near the eye increased slightly.[11] This trend was temporary, as cooler waters and stronger wind shear began affecting Gamede on March 1, leaving the center exposed from the convection. That day, the MFR downgraded Gamede to a severe tropical storm.[12] On March 2, the JTWC discontinued advisories,[6] and the MFR reclassified the storm as an extratropical cyclone. A ridge to its south caused the remnants of Gamede to slow again and execute a small loop southeast of Madagascar. The MFR discontinued advisories on March 4, and the agency tracked the weakening low for two more days at it drifted westward.[4][5]

Preparations[edit]

On St. Brandon, the meteorological staff on the island rode out the storm in the Coast Guard office.[3] In Mauritius, a total of 200 people evacuated to storm shelters due to the cyclone.[13] The Mauritius Meteorological Service issued various tropical cyclone warnings for 66 hours, ultimately raising it to a Class IV warning for 6 hours, the highest warning in which gusts of 120 km/h were recorded and expected to continue.[3]

Officials in Réunion closed schools and also issued a temporary driving ban.[14] Due to the threat of the storm, several flights in and out of Mauritius, Réunion, and Rodrigues were canceled.[15] Fishermen were banned from sailing out to sea.[16]

Impact and records[edit]

Flooding from Gamede on Réunion

With its large circulation, Cyclone Gamede's rainbands affected islands in the south-west Indian Ocean for several days, including St. Brandon, Agaléga, Rodrigues, Mauritius, Réunion, and Madagascar.[3][17] The mean precipitation on the respective islands reached 71 mm (2.8 in) on Rodrigues, 99 mm (3.9 in) on Agaléga, 208 mm (8.2 in) on St. Brandon, 464 mm (18.3 in) on Mauritius,[3] and 5,512 mm (217.0 in) on Réunion.[18]

The storm first affected St. Brandon, where its high tides caused severe beach erosion. The cyclone produced wind gusts of over 160 km/h (99 mph), strong enough to damage window panes and part of an anemometer.[3] Gamede killed two on Mauritius,[13] one of whom drowned in high waves.[14] Wind gusts on Mauritius reached 158 km/h (98 mph),[3] damaging crops and infrastructure, and strong enough to knock out 70% of the island's population.[13] Despite warnings to remain inside, several people ventured outside during the storm.[19]

Rough waves and strong winds affected a cruise ship to the east of Madagascar; several windows were broken, though no serious injuries were reported.[20] Along Madagascar's east coast, Gamede produced squally rain and winds.[17] Gamede had followed shortly after Tropical Cyclones Bondo, Clovis, and Favio, being the fourth tropical cyclone to impact Madagascar in two months.[21]

Réunion[edit]

The large size of the cyclone resulted in several days of very heavy, continuous rainfall in the mountainous region on Réunion island.[18] The island is the location for several tropical cyclone rainfall records; due to the orography of the island, tropical moisture will travel upward to the volcanic peaks, where it cools and codifies into rainfall.[22] The heaviest totals occurred from February 24 through February 28.[18] Commerson's Crater, located at an elevation of 2.3 km (1.4 mi),[4] reported 2463 mm (97 in) in 48 hours, which is just short of the worldwide record set by an unnamed tropical cyclone in April 1958. Gamede broke worldwide rainfall records between three and nine days, with its total precipitation amounting to 5512 mm (217 in) in Commerson's Crater; Cyclone Hyacinthe in 1980 remains the wettest tropical cyclone on record, having produced greater totals after ten days. Several locations on the island reported great totals. In a 24‑hour period, Hell-Bourg reported 1489 mm (58.6 in), and in a 72‑hour period, Cilaos reported 2321 mm (91.4 in).[18]

The broken bridge on the Saint-Étienne river after Gamede

Two people died on the island after attempting to cross rivers during the storm.[23] Nine people were injured on the island,[13] including two who were seriously injured.[24] A peak wind gust of 205 km/h (127 mph) was reported on the island.[14] The passage of the cyclone left about 100,000 homes without power or water on Réunion.[25][24] The rainfall caused some flood damage,[4] and the combination of precipitation and strong winds caused heavy crop damage, including to the sugar cane and banana crops.[14] Several roads and bridges were damaged on the island.[13] A 520 m (1700 ft) bridge over the Saint Etienne River collapsed near Saint-Louis, with the cost estimated at €20 million (2007 EUR, $26 million 2007 USD).[4][14] The bridge, which carried about 50,000 vehicles per day, collapsed as river flow increased from the heavy rainfall; two towns were left temporarily isolated due to the incident.[26]

On June 13, 2007, the government of France provided a relief fund to Réunion of €17.6 million (2007 EUR) in aid, including €9.6 million for farmers affected by the cyclone.[27] The assistance provided €7.7 million for repairing roads and infrastructure, including rebuilding the destroyed bridge over the Saint Etienne River.[27] In the immediate aftermath of the storm, officials deployed army resources to establish a temporary aerial bridge while a new bridge was built.[23]

See also[edit]

Notes[edit]

  1. ^ Météo-France's meteorological office in Réunion (MFR) is the official Regional Specialized Meteorological Center for the South-West Indian Ocean, tracking all tropical cyclones from the east coast of Africa to 90° E.[1]
  2. ^ The Joint Typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force task force that issues advisories for storms in the basin.


References[edit]

  1. ^ Philippe Caroff; et al. (April 2011). Operational procedures of TC satellite analysis at RSMC La Reunion (PDF) (Report). World Meteorological Organization. pp. 4–5. Retrieved 2013-10-27.
  2. ^ World Meteorological Organization (2005). "Seventeenth Session of the RA I Tropical Cyclone Committee for the South-West Indian Ocean" (PDF). Retrieved 2008-04-12.
  3. ^ a b c d e f g h i Technical Report CS 28 Cyclone Season of the South West Indian Ocean 2006 – 2007 (PDF) (Report). Mauritius Meteorological Services. January 2008. Retrieved January 29, 2019.
  4. ^ a b c d e f g h i j Gary Padgett (March 28, 2007). "February 2007 Worldwide Tropical Cyclone Summary". Retrieved January 29, 2019.
  5. ^ a b c d e Kenneth R. Knapp; Michael C. Kruk; David H. Levinson; Howard J. Diamond; Charles J. Neumann (2010). 2007 Gamede (2007050S16079). The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data (Report). Bulletin of the American Meteorological Society. Retrieved January 28, 2019.
  6. ^ a b c 2007 Annual Tropical Cyclone Report (PDF) (Report). Joint Typhoon Warning Center. Retrieved January 28, 2019.
  7. ^ Météo-France (February 22, 2007). "Severe Tropical Storm Gamede Warning 009". Retrieved January 29, 2019.
  8. ^ Météo-France (February 23, 2007). "Tropical Cyclone Gamede Warning 010". Retrieved January 29, 2019.
  9. ^ "Season 1965-1966 Tropical Cyclone DENISE Track Map". australiasevereweather.com. Retrieved 2009-08-12.
  10. ^ Fourth tropical cyclone in four months, nears the coast. Integrated Regional Information Networks (Report). March 13, 2007. ReliefWeb. Retrieved January 29, 2019.
  11. ^ Météo-France (February 28, 2007). "Tropical Cyclone Gamede Warning 033". Retrieved January 29, 2019.
  12. ^ Météo-France (March 1, 2007). "Tropical Cyclone Gamede Warning 037". Retrieved January 29, 2019.
  13. ^ a b c d e "Africa Weekly Spotlight" (PDF). International Strategy for Disaster Reduction. 2007-03-05. Retrieved 2008-01-28.
  14. ^ a b c d e Sapa (2007-02-25). "Cyclone Gamede sweeps over Indian Ocean islands". Agence France-Presse. Retrieved 2008-04-12.
  15. ^ Le Mauricien (2007-02-27). "Gamede comeback disrupts operations at airport".
  16. ^ Safi Fele (2007). "Le cyclone Gamède poursuit sa route destructrice vers Madagascar". Afrik.com. Retrieved 2008-10-26.
  17. ^ a b "Africa: Weather Hazards Assessments for March 1–7, 2007". Famine Early Warning System Network. 2007-02-28. Retrieved 2008-01-28.
  18. ^ a b c d Météo-France (2007). "Avec GAMEDE et 27 ans après HYACINTHE, La Réunion bat ses propres records mondiaux de précipitations sur les durées de 3 à 9 jours" (in French). Archived from the original on March 22, 2007. Retrieved 2008-04-12.
  19. ^ Africa News (2007-02-28). "Legislation Needed to Force People Inside During Cyclones".
  20. ^ David Sanderson (2007-03-05). "Cruise liner stranded in remote port by cyclone". London: The Times Online. Retrieved 2008-04-12.
  21. ^ "Madagascar: Fifth cyclone hits island bulletin no. 1/2007". International Federation of Red Cross and Red Crescent Societies. 2007-03-17. Retrieved 2008-01-28.
  22. ^ Paul Simons (2007-03-19). "Tropical rainfall provides a Reunion to remember". The Times (London).
  23. ^ a b Le Figaro (2007-02-28). "Gamède fait deux morts à la Réunion". Retrieved 2008-06-01.
  24. ^ a b Associated Press (2007-02-26). "Cyclone cuts off water, electricity for many on Reunion Island". USA Today. Retrieved 2008-04-12.
  25. ^ "El ciclón Gamede azota Isla Reunión" (in French). Isla Reunión. 2007. Retrieved 2008-10-26.
  26. ^ Le Figaro (2007-02-24). "La Réunion très choquée". Retrieved 2008-06-01.
  27. ^ a b Maire Info (2007-06-15). "7,7 millions d'euros contribueront à la réparation des dégâts aux infrastructures essentielles des collectivités territoriales" (in French). Retrieved 2008-04-12.

External links[edit]