Intense Tropical 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
The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by t ...
. The seventh named storm of the
2006–07 South-West Indian Ocean cyclone season, Gamede formed south of
Diego Garcia
Diego Garcia is an island of the British Indian Ocean Territory, a disputed overseas territory of the United Kingdom. It is a militarised atoll just south of the equator in the central Indian Ocean, and the largest of the 60 small islands of ...
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
The Mascarene Islands (, ) or Mascarenes or Mascarenhas Archipelago is a group of islands in the Indian Ocean east of Madagascar consisting of the islands belonging to the Republic of Mauritius as well as the French department of Réunion. Their ...
as an intense tropical cyclone, during which it reached 10 minute
maximum sustained winds of winds of , according to the
Météo-France meteorological office in
Réunion (MFR). The American-based
Joint Typhoon Warning Center
The Joint typhoon Warning Center (JTWC) is a joint United States Navy – United States Air Force command in Pearl Harbor, Hawaii. The JTWC is responsible for the issuing of tropical cyclone warnings in the North-West Pacific Ocean, South P ...
(JTWC) estimated peak 1 minute winds of , equivalent to a Category 3 on the
Saffir–Simpson scale
The Saffir–Simpson hurricane wind scale (SSHWS) classifies hurricanes—which in the Western Hemisphere are tropical cyclones that exceed the intensities of tropical depressions and tropical storms—into five categories distinguished b ...
. 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
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
. The MFR tracked the storm for four more days.
Cyclone Gamede first passed near
St. Brandon, where its wind gusts damaged a few windows. When the storm stalled for a few days, it resulted in a prolonged period of heavy rainfall and high tides for the
Mascarene Islands
The Mascarene Islands (, ) or Mascarenes or Mascarenhas Archipelago is a group of islands in the Indian Ocean east of Madagascar consisting of the islands belonging to the Republic of Mauritius as well as the French department of Réunion. Their ...
. A
pluviometer
A rain gauge (also known as udometer, pluvia metior, pluviometer, ombrometer, and hyetometer) is an instrument used by meteorologists and hydrologists to gather and measure the amount of liquid precipitation over a predefined area, over a period ...
at
Commerson Crater
Commerson Crater is a caldera in the mountains of Réunion, an overseas department of France. Located in the municipal territory of Saint-Joseph, it is part of the Piton de la Fournaise, a shield volcano on the eastern end of Réunion Island, ...
recorded worldwide record rainfall amounts over a period of 3–9 days, with a total of 5512 mm (217 in). Only
Cyclone Hyacinthe
Tropical Cyclone Hyacinthe was the wettest tropical cyclone on record worldwide. The eighth named storm of the season, Hyacinthe formed on January 15, 1980, to the northeast of Mauritius in the southern Indian Ocean. Initially it moved to t ...
in 1980 had a higher recorded rainfall total. The deluge from Gamede caused flooding damage across Réunion, washing out a bridge in the southern portion of the island. Monetary damage on Réunion was estimated at over €165 million (US$120 million). Two people each were killed on Réunion and nearby Mauritius. The storm's outer rainbands affected southeastern Madagascar, becoming the fourth tropical cyclone to affect the country in two months. Later, high waves from Gamede flooded coastal portions of the
South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
n province of
KwaZulu-Natal.
Meteorological history
The
Intertropical Convergence Zone was active across the Indian Ocean in the middle of February 2007, which spawned a
low-pressure area
In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...
southeast of
Diego Garcia
Diego Garcia is an island of the British Indian Ocean Territory, a disputed overseas territory of the United Kingdom. It is a militarised atoll just south of the equator in the central Indian Ocean, and the largest of the 60 small islands of ...
on February 18.
The system developed
convection
Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the conve ...
, or thunderstorms, over a weak, but well-defined low-level circulation.
The MFR first began tracking the system as a tropical disturbance on February 19.
An
anticyclone
An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from ...
over the nascent system provided weak
wind shear
Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizont ...
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.
By late on February 20, the system had organized enough for the MFR to upgrade the disturbance to a tropical depression,
and for the JTWC to issue a
Tropical Cyclone Formation Alert
A Tropical Cyclone Formation Alert (TCFA) is a bulletin released by the U.S. Navy-operated Joint Typhoon Warning Center in Honolulu, Hawaii or the Fleet Weather Center in Norfolk, Virginia, warning of the possibility of a tropical cyclone formin ...
.
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.
As Gamede continued to intensify, its track shifted to the west-southwest.
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.
An
eye became evident on satellite imagery, a sign of the storm's development. The MFR upgraded Gamede to
tropical cyclone status on February 23, noting that the system was "very broad". Soon after, the cyclone moved over
St. Brandon, one of the
Outer Islands of Mauritius; the island recorded a minimum
barometric pressure
Atmospheric pressure, also known as barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1013.25 millibars, 7 ...
of , and estimated the eyewall diameter at 50 km (30 mi).
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 late on February 25. At the same time, the JTWC estimated peak 1 minute winds of .
While remaining nearly stationary northwest of the Mascarene Islands, Gamede lost some of its deep convection due to
upwelling
Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted surface water. The nut ...
, the process in which a stationary storm causes the water temperatures to decrease by bringing the cooler, deeper waters to the surface.
Early forecasts suggested the possibility that the cyclone would turn westward and strike
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
near
Toamasina
Toamasina (), meaning "like salt" or "salty", unofficially and in French Tamatave, is the capital of the Atsinanana region on the east coast of Madagascar on the Indian Ocean. The city is the chief seaport of the country, situated northeast of it ...
.
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.
On the next day, the convection near the eye increased slightly. 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. On March 2, the JTWC discontinued advisories,
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.
Preparations
On St. Brandon, the meteorological staff on the island rode out the storm in the Coast Guard office.
In
Mauritius
Mauritius ( ; french: Maurice, link=no ; mfe, label= Mauritian Creole, Moris ), officially the Republic of Mauritius, is an island nation in the Indian Ocean about off the southeast coast of the African continent, east of Madagascar. It ...
, a total of 200 people evacuated to storm shelters due to the cyclone.
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.
Officials in
Réunion closed schools and also issued a temporary driving ban.
Due to the threat of the storm, several flights in and out of Mauritius, Réunion, and
Rodrigues were canceled. Fishermen were banned from sailing out to sea.
Impact
With its large circulation, Cyclone Gamede's rainbands affected islands in the south-west Indian Ocean for several days. The storm first affected St. Brandon, where its high tides caused severe
beach erosion. The cyclone produced wind gusts of over , strong enough to damage window panes and part of an
anemometer
In meteorology, an anemometer () is a device that measures wind speed and direction. It is a common instrument used in weather stations. The earliest known description of an anemometer was by Italian architect and author Leon Battista Alberti ...
. Rainfall on the island reached . Gamede passed south of Agaléga, dropping of rainfall over a four-day period. The storm's rainfall reached on
Rodrigues.
Rough waves and strong winds affected a cruise ship to the east of Madagascar; several windows were broken, though no serious injuries were reported. Gamede lashed Madagascar's east coast with
squall
A squall is a sudden, sharp increase in wind speed lasting minutes, as opposed to a wind gust, which lasts for only seconds. They are usually associated with active weather, such as rain showers, thunderstorms, or heavy snow. Squalls refer to the ...
s of heavy rainfall and gusty winds, affecting areas struck by
Tropical Storm Clovis two months earlier.
Gamede had followed shortly after Tropical Cyclones Bondo, Clovis, and Favio, being the fourth tropical cyclone to impact Madagascar in two months.
High waves also struck the South African province of
KwaZulu-Natal, forcing the temporary closure of beaches, roads, and the
Port of Durban
The Port of Durban, commonly called Durban Harbour, is the largest and busiest shipping terminal in sub-Saharan Africa. It handles up to 31.4 million tons of cargo each year. It is the fourth largest container terminal in the Southern Hemisp ...
.
Mauritius
Remaining near the Mascarene Islands for several days, Gamede dropped heavy rainfall on Mauritius, reaching . Winds on the island reached at Fort Williams in
Port Louis
Port Louis (french: Port-Louis; mfe, label= Mauritian Creole, Polwi or , ) is the capital city of Mauritius. It is mainly located in the Port Louis District, with a small western part in the Black River District. Port Louis is the country's e ...
.
Gamede killed two on Mauritius,
one of whom drowned in high waves.
The storm damaged crops and infrastructure, with power knocked out to 70% of the island's population.
Despite warnings to remain inside, several people ventured outside during the storm.
Réunion
The large size of the cyclone resulted in several days of very heavy, continuous rainfall in the mountainous region on
Réunion island. The heaviest totals occurred from February 24 through February 28,
with a nine-day total of 5512 mm (217 in) at
Commerson Crater
Commerson Crater is a caldera in the mountains of Réunion, an overseas department of France. Located in the municipal territory of Saint-Joseph, it is part of the Piton de la Fournaise, a shield volcano on the eastern end of Réunion Island, ...
. Several locations on the island reported great totals. In a 24‑hour period,
Hell-Bourg
Hell-Bourg is a small village in the Salazie commune (administrative division) of the French overseas department of Réunion. It is the main community in the island's Cirque de Salazie, and is named for the respected former admiral and island ...
reported 1489 mm (58.6 in), and in a 72‑hour period,
Cilaos
Cilaos () is a town and commune on the French island of Réunion in the Indian Ocean. It is located centrally on the island, in a caldera of altitude 1,214 m. The caldera (usually known as the 'Cirque') is also named for the community.
History
...
reported 2321 mm (91.4 in).
A peak wind gust of was reported on the island.
Gamede produced the highest waves along the north and west coast of Réunion in 50 years, with a maximum wave heights of at Pointe du Gouffre.
The prolonged high waves eroded beaches and washed away the promenade at
Le Port.
Monetary damage on Réunion from Gamede was at least €165 million (US$120 million).
Two people died on the island after attempting to cross rivers during the storm.
At least 90 people were injured due to the storm,
including two who were seriously injured.
The passage of the cyclone left about 100,000 homes without power or water on Réunion.
High floodwaters damaged a dyke along the north bank of the
Rivière des Galets.
Gamede caused heavy crop damage, including to the sugar cane and banana crops.
Several roads and bridges were damaged on the island.
Floods damaged roads in
Saint-André and
Salazie
Salazie () is a volcanic caldera and commune (administrative division) in the department and region of Réunion.
The first settlement of the area took place in 1829 after a cyclone had devastated the nearby coast, and the municipality of Sal ...
,
and washed out a 520 m (1700 ft) bridge over the Saint Etienne River, part of
Route nationale 1
The Route nationale 1 is a trunk road ( nationale) in France between Paris and Calais. It is approximately long.
Reclassification
The majority of the original road has been superseded by the A16 autoroute. As a result, much of the road has no ...
connecting
Saint-Louis and
Saint-Pierre.
The bridge outage left the two towns temporarily isolated.
Aftermath and records
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.
The assistance provided €7.7 million for repairing roads and infrastructure, including rebuilding the destroyed bridge over the Saint Etienne River.
In the immediate aftermath of the storm, officials deployed army resources to establish a temporary aerial bridge while a new bridge was built.
The replacement bridge was opened in June 2013.
Réunion island is the location for several tropical cyclone rainfall records; due to the
orography
Orography is the study of the topographic relief of mountains, and can more broadly include hills, and any part of a region's elevated terrain. Orography (also known as ''oreography'', ''orology'' or ''oreology'') falls within the broader discip ...
of the island, tropical moisture will travel upward to the volcanic peaks, where it cools and codifies into rainfall.
Commerson Crater
Commerson Crater is a caldera in the mountains of Réunion, an overseas department of France. Located in the municipal territory of Saint-Joseph, it is part of the Piton de la Fournaise, a shield volcano on the eastern end of Réunion Island, ...
, located at an elevation of 2.3 km (1.4 mi),
recorded historic rainfall accumulations during the passage of Gamede. The location 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. Over 72 hours, Commerson Crater recorded , which surpassed the previous worldwide record for that duration, set by
Cyclone Hyacinthe
Tropical Cyclone Hyacinthe was the wettest tropical cyclone on record worldwide. The eighth named storm of the season, Hyacinthe formed on January 15, 1980, to the northeast of Mauritius in the southern Indian Ocean. Initially it moved to t ...
in 1980. The station also broke rainfall records for precipitation totals between four and nine days, with a storm total of 5512 mm (217 in) in Commerson Crater.
Hyacinthe in 1980 dropped over 14 days, also at Commerson Crater.
See also
*
List of wettest tropical cyclones
This is a list of the wettest tropical cyclones, listing all tropical cyclones known to have dropped at least of precipitation on a single location. Data is most complete for Australia, Cuba, Dominican Republic, Japan, Hong Kong, Mexico, Yap, Chu ...
*
List of wettest tropical cyclones by country
This is a list of wettest tropical cyclones by country, using all known available sources. Data is most complete for Australia, Cuba, Dominican Republic, Japan, Hong Kong, Mexico, Taiwan, Micronesia's Yap and Chuuk, and the United States, with ...
*
Tropical cyclones in the Mascarene Islands
*
Cyclone Dina
Notes
References
External links
La Réunion - Météo-France Report on Cyclone Gamede (French)
{{DEFAULTSORT:Gamede
2006–07 South-West Indian Ocean cyclone season
Tropical cyclones in the Mascarene Islands
Intense Tropical Cyclones
Tropical cyclones in 2007