{{Short description|South-West Indian cyclone in 1980}} {{good article}} {{Infobox weather event | image = Hyacinthe 1980-01-25 0326Z.png | caption = Cyclone Hyacinthe on January 25 | formed = {{start-date|January 15, 1980}} | dissipated = {{end-date|January 31, 1980}} | extratropical = January 29, 1980 }}{{Infobox weather event/MF | winds = 90 | pressure = 960 }}{{Infobox weather event/JTWC | winds = 70 }}{{Infobox weather event/Effects | deaths = 25 | year = 1980 | damages = 167000000 | affected = Mauritius, Réunion, Madagascar }}{{Infobox weather event/Footer | season = 1979–80 South-West Indian Ocean cyclone season }} '''Intense Tropical Cyclone Hyacinthe''' was the wettest tropical cyclone on record worldwide. The eighth named storm of the 1979–80 South-West Indian Ocean cyclone season, Hyacinthe formed on January 15, 1980, to the northeast of Mauritius in the southern Indian Ocean. Initially it moved to the west-southwest, and while slowly intensifying it passed north of the French overseas department of Réunion. On January 19, Météo-France estimated that the storm had intensified to a tropical cyclone. Hyacinthe looped to the south of eastern Madagascar and weakened, although it restrengthened after turning to the east. The storm executed another loop to the southwest of Réunion, passing near the island for a second and later third time. Hyacinthe became extratropical on January 29 after turning southward, dissipating two days later.
For twelve days, Hyacinthe dropped torrential rainfall on Réunion; nearly all of the island received more than {{convert|1|m|ft|abbr=on}} of precipitation. Over a 15-day period from January 14 to January 28, {{convert|6083|mm|in|abbr=on}} of rainfall were recorded at Commerson Crater, a volcano caldera. The heaviest rainfall occurred through a process called orographic lift in the mountainous interior, leading to hundreds of landslides. Widespread floods damaged half the roads on Réunion and isolated three villages. Hyacinthe caused heavy damage to crops and damaged or destroyed 2,000 houses. Losses from the storm totaled $167 million (1980 USD, 676 million francs),{{#tag:ref|All damage totals are reported in 1980 United States dollars with the original French franc total in parentheses.|group="nb"}} and 25 people were killed.
==Meteorological history== {{storm path|Hyacinthe 1980 track.png}} In the middle of January 1980, the Intertropical Convergence Zone persisted along 10° S, spawning a small low-level circulation near St. Brandon.<ref name="mad">{{cite journal|title=La Saison Cyclonique 1979-1980 A Madagascar|year=1981|author=La Météorlogie, Service de la Réunion|page=116|journal=Madagascar: Revue de Géographie|access-date=2013-04-13|language=French|url=http://madarevues.recherches.gov.mg/IMG/pdf/rev-geo38_7_.pdf|volume=38|issue=Janv-Juin 1981}}</ref> According to Météo-France (MFR), a tropical depression formed about {{convert|355|km|mi|abbr=on}} northeast of Mauritius on January 15.{{#tag:ref|Météo-France is the official Regional Specialized Meteorological Center for the south-west Indian Ocean, based out of Réunion.<ref>{{cite report|publisher=National Hurricane Center|date=2011-09-11|title=Worldwide Tropical Cyclone Centers|access-date=2012-08-27|url=https://www.nhc.noaa.gov/aboutrsmc.shtml}}</ref> |group="nb"}} It tracked to the west-southwest, passing north of the island on January 17.<ref name="mf">{{cite report|publisher=Météo-France |title=Donnes de Hyacinthe |url=http://www.meteo.fr/temps/domtom/La_Reunion/base_cyclone/nom_annee/HYACINTHE_1979.html |access-date=2013-04-12 |url-status=dead |archive-url=https://web.archive.org/web/20050130042647/http://www.meteo.fr/temps/domtom/La_Reunion/base_cyclone/nom_annee/HYACINTHE_1979.html |archive-date=January 30, 2005 }}</ref> That day, the Joint Typhoon Warning Center (JTWC) also reported that a tropical depression had developed, giving it the identifier "08S". Shortly thereafter, the JTWC upgraded the depression to a tropical storm,<ref name="jtwc">{{cite report|publisher=Joint Typhoon Warning Center|title=Best Track for Tropical Cyclone 08S|access-date=2013-04-12|url=http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/best_tracks/1980/1980s-bsh/bsh081980.txt|format=TXT|archive-date=2013-04-06|archive-url=https://web.archive.org/web/20130406150752/http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/best_tracks/1980/1980s-bsh/bsh081980.txt|url-status=dead}}</ref> and the MFR followed suit on January 18, naming the storm ''Hyacinthe''.<ref name="mf"/> The storm gradually intensified as it passed north of Réunion, with 1-minute winds of {{convert|110|km/h|mph|abbr=on}} by January 19, according to the JTWC.<ref name="jtwc"/> That day, an eye developed,<ref name="mad"/> and MFR estimated that Hyacinthe intensified to tropical cyclone status, with 10-minute winds of {{convert|120|km/h|mph|abbr=on}}.<ref name="mf"/> A strengthening anticyclone to the south turned the storm northwestward,<ref name="mad"/> and on January 20, Hyacinthe executed a small loop to the south, just offshore eastern Madagascar.<ref name="mf"/>
While moving to the south, Hyacinthe's winds steadily decreased, as the storm weakened. On January 21, the storm weakened below tropical cyclone intensity,<ref name="mf"/> and on January 22 the JTWC estimated winds decreased to {{convert|75|km/h|mph|abbr=on}}. The next day, it turned to the east while slowly re-intensifying. On January 24, the JTWC upgraded Hyacinthe to the equivalent of a minimal hurricane, with winds of {{convert|120|km/h|mph|abbr=on}}. After approaching within {{convert|175|km|mi|abbr=on}} west-southwest of Réunion, the cyclone turned to the northwest and executed another loop. The JTWC estimated that Hyacinthe reached peak winds of {{convert|130|km/h|mph|abbr=on}} on January 25, which the storm maintained for about 24 hours. During that time, Hyacinthe turned to the southeast and later weakened. On January 26, it moved near Réunion for the third time, passing about {{convert|105|km|mi|abbr=on}} to the south.<ref name="jtwc"/> The storm turned southward, becoming extratropical on January 29. Over the next two days, the remnants of Hyacinthe accelerated, turned to the east, and dissipated to the southeast of Madagascar.<ref name="mf"/>
==Impact== right|thumb|Washed out road in Saint-Pierre, Réunion For twelve days, the circulation of the storm produced cloudiness and thunderstorms over Réunion.<ref name="risques">{{cite report|title=Synthés des Événements: Hyacinthe Cyclone Tropical (16 au 27 janvier 1980)|language=French|publisher=Les Risques Naturales á la Réunion|access-date=2013-04-13|url=http://www.risquesnaturels.re/pdf/EVENEMENTS_HISTORIQUES/evenement_historique_Hyacinthe.pdf}}</ref> Hyacinthe broke several rainfall records for tropical cyclones, becoming the wettest tropical cyclone on record.<ref name="bams"/> From January 14 to January 28, the storm dropped {{convert|6083|mm|in|abbr=on}} at Commerson Crater,<ref>{{cite report|publisher=Meteo France|title=Précipitations extrêmes|access-date=2013-04-15|url=http://www.meteo.fr/temps/domtom/La_Reunion/meteoreunion2/climatologie/records/rec_RR1.html}}</ref> just north of the Piton de la Fournaise volcano.<ref name="bams2"/> Over ten days, Hyacinthe produced {{convert|5,678|mm|in|abbr=on}}, also at Commerson.<ref name="tcfaq">{{cite report|author=Chris Landsea|date=2007-03-12|title=Subject: E4) What are the largest rainfalls associated with tropical cyclones?|publisher=Hurricane Research Division|access-date=2013-04-12|url=https://www.aoml.noaa.gov/hrd/tcfaq/E4.html}}</ref> In twelve hours, Hyacinthe dropped {{convert|1,095|mm|in|abbr=on}} of rainfall at Grand Îlet, just {{convert|49|mm|in|abbr=on}} shy of the record set by Cyclone Denise in 1966.<ref name="bams"/> The highest daily total was on January 25, when {{convert|1140|mm|in|abbr=on}} fell at Commerson.<ref name="risques"/> Over a three-day period, the storm dropped {{convert|3,240|mm|in|abbr=on}} at Commerson, as well as {{convert|4,300|mm|in|abbr=on}} over a five-day period ending on January 28.<ref name="bams">{{cite journal|pages=856, 858|title=Extreme Weather Records|author=Randall S. Cerveny|journal=Bulletin of the American Meteorological Society|date=June 2007|volume=88 |issue=6 |doi=10.1175/BAMS-88-6-853|display-authors=etal|bibcode = 2007BAMS...88..853C |doi-access=free}}</ref> Only a small portion of the island near Saint-Pierre received less than {{convert|1|m|ft|abbr=on}} of rainfall, and totals increased further inland,<ref name="risques"/> with over {{convert|2|m|ft|abbr=on}} recorded at four locations.<ref name="bams2">{{cite journal|page=606|title=World-Record Rainfalls During Tropical Cyclone Gamede|author=Hubert Quetelard|journal=Bulletin of the American Meteorological Society|date=May 2009|volume=90 |issue=5 |doi=10.1175/2008BAMS2660.1|display-authors=etal|bibcode = 2009BAMS...90..603Q |doi-access=free}}</ref> Such heavy rainfall typically occurs on the island when tropical cyclones approach, owing to orographic enhancement in the mountainous interior.<ref name="bams2"/>
In addition to the rainfall, Hyacinthe produced a minimum barometric pressure of {{convert|977.8|mbar|inHg|abbr=on}} at Saint-Pierre on January 27. Wind gusts reached {{convert|150|km/h|mph|abbr=on}} in Saint-Denis, although the mountainous portion of the island reported winds as strong as {{convert|180|km/h|mph|abbr=on}}. Wave action was not severe due to the quick changes in track and lack of significant intensity. There was some beach erosion along western-facing beaches, and Pointe des Galets sustained damage to coastal properties.<ref name="risques"/> However, any major damage caused by the storm was largely due to the heavy rainfall. The Rivière Langevin reported increased flow, reaching a discharge of about 300 m<sup>3</sup>/s (10,500 ft<sup>3</sup>/s).<ref>{{cite web|author=Naomi Erika |author2=Karine Élodie |title=Le Cyclone Hyacinthe |access-date=2013-04-12 |publisher=Collège Les Tamarins |url=http://pedagogie2.ac-reunion.fr/cotamarp/temps/cyclone/historique/hyacinthegroupe10.htm |language=French |url-status=dead |archive-url=https://web.archive.org/web/20160307160708/http://pedagogie2.ac-reunion.fr/cotamarp/temps/cyclone/historique/hyacinthegroupe10.htm |archive-date=2016-03-07 }}</ref> Along Rivière-du-Mat les Bas, river flooding entered five houses. Floods washed out a {{convert|30|m|ft|abbr=on}} and a {{convert|60|m|ft|abbr=on}} portion of a highway along a ravine near Chaudron. Along Route nationale 1, traffic was disrupted after rocks blocked the roadway. In Petite-Île, floods washed out a bridge and {{convert|200|m|ft|abbr=on}} of roads.<ref name="risques"/> About half of the roads on Réunion were damaged,<ref name="mwl"/> and road damage was estimated at $40 million (1980 USD, 161.3 million francs). The rain caused widespread mudslides, including hundreds near Salazie and Cilaos.<ref name="risques"/> Three towns were temporarily isolated,<ref name="risques"/> including Hell-Bourg which was cut off for about eight days,<ref>{{cite news|title=Salazie en pole position dans la course des téléphériques|date=2013-04-10|newspaper=Le Journal de I'île Reunion|access-date=2013-04-13|url=http://www.clicanoo.re/364128-salazie-en-pole-position-dans-la-course-des-telepheriques.html}}{{Dead link|date=August 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Helicopters delivered food and clothing to the villages.<ref name="risques"/>
Throughout Réunion, Hyacinthe killed 25 people and left 7,000 homeless.<ref>{{cite report|author=Office of U.S. Foreign Disaster Assistance|title=Significant Data on Major Disasters Worldwide 1900-present|date=August 1993|access-date=2013-04-12|url=http://pdf.usaid.gov/pdf_docs/PNABP986.pdf|archive-url=https://web.archive.org/web/20110718110440/http://pdf.usaid.gov/pdf_docs/PNABP986.pdf|url-status=dead|archive-date=July 18, 2011}}</ref> Four of the deaths occurred after a house was washed away at Petite-Île. A school was destroyed in Saint-Louis. The storm caused power and water outages, and about 30% of the island temporarily lost phone service. Hyacinthe damaged 1,712 houses and destroyed another 288; housing damage totaled about $42 million (1980 USD, 170 million francs). Flooding caused $48 million (1980 USD, 194 million francs) in agricultural damage, including about 1,000 killed cattle and near-total losses to bananas, mangoes, and avocados. Overall damage was estimated at $167 million (676 million francs).<ref name="risques"/> Many records set by the storm were broken by Cyclone Gamede in 2007, including the rainfall accumulations from three to eight days.<ref>{{cite journal|page=577|title=State of the Climate in 2007|author=D. H. Levinson|author2=J. H. Lawrimore|journal=Bulletin of the American Meteorological Society|access-date=2013-04-12|date=July 2008|volume=89 |issue=7 |url=http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-89-7-StateoftheClimate|format=PDF|doi=10.1175/BAMS-89-7-StateoftheClimate|bibcode=2008BAMS...89S...1L|url-access=subscription}}{{Dead link|date=April 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> However, Hyacinthe retained its status as the wettest overall tropical cyclone.<ref name="tcfaq"/>
Elsewhere, Hyacinthe affected Madagascar as a weaker storm. Wind gusts reached {{convert|126|km/h|mph|abbr=on}} at Mananjary and {{convert|111|km/h|mph|abbr=on}} on Île Sainte-Marie. At the same two locations, rainfall reached {{convert|207|and|134|mm|in|abbr=on}}, respectively.<ref name="mad"/> On Mauritius, the storm's passage forced the main port to close.<ref name="mwl">{{cite journal|page=201|title=Hurricane Alley|author=Dick DeAngelis|journal=Mariners Weather Log|date=May–June 1980|volume=24|number=3|publisher=United States Department of Commerce}}</ref>
==See also== {{Portal|Tropical cyclones}} {{Commons category|Cyclone Hyacinthe}} * List of wettest tropical cyclones by country * Tropical cyclones in the Mascarene Islands * Cyclone Dina (2002) – produced heavy rainfall on Réunion.
==Notes== {{Reflist|group=nb}}
==References== {{reflist}}
{{DEFAULTSORT:Hyacinthe}} Hyacinthe Category:Tropical cyclones in the Mascarene Islands Category:Cyclones in Madagascar Category:South-West Indian Ocean tropical cyclones Hyacinthe