Просмотр кода страницы Английская Википедия:1985–86 South-West Indian Ocean cyclone season

{{Английская Википедия/Панель перехода}}
{{short description|Cyclone season in the Southwest Indian Ocean}}
{{good article}}
{{Infobox hurricane season
| Basin=SWI
| Year=1986
| Track=1985-1986 South-West Indian Ocean cyclone season summary.jpg
| First storm formed=December 23, 1985
| Last storm dissipated=May 10, 1986
| Strongest storm name=Erinesta
| Strongest storm pressure=927
| Strongest storm winds=92
| Average wind speed=10
| Total disturbances=13
| Total depressions=13
| Total storms=12
| Total hurricanes=5
| Total intense=1
| Fatalities=99
| Damages=150
| five seasons=[[1983–84 South-West Indian Ocean cyclone season|1983–84]], [[1984–85 South-West Indian Ocean cyclone season|1984–85]], '''1985–86''', [[1986–87 South-West Indian Ocean cyclone season|1986–87]], [[1987–88 South-West Indian Ocean cyclone season|1987–88]]
| Australian season=1985–86 Australian region cyclone season
| South Pacific season=1985–86 South Pacific cyclone season
}}
The '''1985–86 South-West Indian Ocean cyclone season''' was the first in which the [[Météo-France]] office (MFR) on [[Réunion]] tracked cyclones as far east as [[90th meridian east|90°&nbsp;E]] in [[Indian Ocean]], south of the [[equator]]. Previously, the agency's area of responsibility was limited to [[80th meridian east|80°&nbsp;E]]. It was an active season with twelve [[tropical cyclone naming|named storms]], of which five strengthened into [[Tropical cyclone scales#South-West Indian Ocean|tropical cyclone]] with 10&nbsp;minute [[maximum sustained wind|sustained winds]] of at least {{convert|120|km/h|mph|abbr=on|round=5}}.{{#tag:ref|All wind speeds in the article are [[maximum sustained wind|sustained]] over 10&nbsp;minute, unless otherwise stated.|group="nb"}} The first named storm was Tropical Storm Alifredy, which originated in the [[Mozambique Channel]] in late December and moved across [[Madagascar]]. However, the unofficial [[Joint Typhoon Warning Center]] (JTWC) tracked a short-lived storm in September.

Most of the activity occurred in 1986, with four storms in January, three of which briefly existed simultaneously on January&nbsp;10. The first of these three, Tropical Storm Berobia, struck eastern [[Mozambique]]. Tropical Storm Costa was a series of three tropical depressions within the same broader system that persisted for 12&nbsp;days, bringing gusty winds and rainfall to the [[Mascarene Islands]]. The strongest storm of the season, Erinesta, formed in late January and struck the tiny [[Tromelin Island]], decimating the native rabbit population. Erinesta later produced {{convert|1643|mm|in|abbr=on}} of rainfall in the mountainous peaks of Réunion, one of the highest 24‑hour rainfall totals at the time at [[Cilaos]]. Two other storms in February – Filomena and Gista – moved southward for their durations and did not significantly impact land. In March, [[Cyclone Honorinina]] killed 99&nbsp;people and caused $150&nbsp;million (1986&nbsp;[[United States dollar|USD]]) in damage when it struck eastern Madagascar. There were two other storms in March, Iarima and Jefotra, the latter of which brushed [[Rodrigues]] island with gusty winds. The final two storms of the season, Krisostoma and Lila, entered from the [[1985–86 Australian region cyclone season|Australian basin]] in April and May, respectively, with Lila exiting the basin to end the season on May&nbsp;10.

== Seasonal summary ==

<div style="text-align: center;">
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   barset:break
  from:23/12/1985 till:27/12/1985 color:TD text:"Alifredy (TD)"
  from:05/01/1986 till:10/01/1986 color:TS text:"Berobia (TS)"
  from:07/01/1986 till:19/01/1986 color:ST text:"Costa (STS)"
  from:10/01/1986 till:19/01/1986 color:TC text:"Delifinina (TC)"
  from:29/01/1986 till:11/02/1986 color:IT text:"Erinesta (ITC)"
  from:05/02/1986 till:12/02/1986 color:TS text:"Filomena (TS)"
   barset:break
  from:18/02/1986 till:25/02/1986 color:ST text:"Gista (STS)"
  from:07/03/1986 till:23/03/1986 color:TC text:"[[Cyclone Honorinina|Honorinina (TC)]]"
  from:13/03/1986 till:18/03/1986 color:TS text:"Iarima (TS)"
  from:27/03/1986 till:05/04/1986 color:TC text:"Jefotra (TC)"
  from:10/04/1986 till:13/04/1986 color:ST text:"Alison-Krisostoma (STS)"
  from:09/05/1986 till:10/05/1986 color:TC text:"Billy-Lila (TC)"

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  from:01/09/1985 till:01/10/1985 text:September
  from:01/10/1985 till:01/11/1985 text:October
  from:01/11/1985 till:01/12/1985 text:November
  from:01/12/1985 till:01/01/1986 text:December
  from:01/01/1986 till:01/02/1986 text:January
  from:01/02/1986 till:01/03/1986 text:February
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</div>
{{clear}}
[[File:01S Sept 25 1985 0243Z.png|thumb|right|Satellite image of the unofficial September tropical storm]]
During the season, the [[Météo-France]] office (MFR) on [[Réunion]] island issued warnings in tropical cyclones within the basin. Using satellite imagery from [[National Oceanic and Atmospheric Administration]], the agency estimated intensity through the [[Dvorak technique]], and warned on tropical cyclones in the region from the coast of Africa to 90°&nbsp;E, south of the equator. In September 1985, their area of responsibility shifted from 80°&nbsp;E to the current 90°&nbsp;E, although lack of satellite imagery along the eastern periphery prevented complete coverage. The [[World Meteorological Organization]] would later label the MFR as a [[Regional Specialized Meteorological Center]] in 1993.<ref name="car">{{cite report|author=Philippe Caroff|date=June 2011|title=Operational procedures of TC satellite analysis at RSMC La Reunion|publisher=World Meteorological Organization|access-date=2013-04-22|url=http://www.wmo.int/pages/prog/www/tcp/documents/RSMCLaReunionforIWSATC.pdf|format=PDF|display-authors=etal|archive-date=2013-10-29|archive-url=https://web.archive.org/web/20131029202727/http://www.wmo.int/pages/prog/www/tcp/documents/RSMCLaReunionforIWSATC.pdf|url-status=live}}</ref> The [[Joint Typhoon Warning Center]] (JTWC), which is a joint [[United States Navy]]&nbsp;– [[United States Air Force]] task force, also issued tropical cyclone warnings for the southwestern Indian Ocean.<ref name="atcr"/> The season's twelve&nbsp;[[tropical cyclone naming|named storms]] was well above the average of nine, while the five [[Tropical cyclone scales#South-West Indian Ocean|tropical cyclones]] – storms attaining [[maximum sustained wind]]s of at least {{convert|120|km/h|mph|abbr=on}} – was average.<ref>{{cite web|author=Chris Landsea|author2=Sandy Delgado|title=Subject: E10) What are the average, most, and least tropical cyclones occurring in each basin?|series=Frequently Asked Questions|date=2014-05-01|publisher=Hurricane Research Division|access-date=2014-10-13|url=http://www.aoml.noaa.gov/hrd/tcfaq/E10.html|archive-date=2012-07-31|archive-url=https://web.archive.org/web/20120731201905/http://www.aoml.noaa.gov/hrd/tcfaq/E10.html|url-status=live}}</ref>

The MFR considered the tropical cyclone year to begin on August&nbsp;1 and continue to July&nbsp;31 of the following year.<ref name="car"/> By December 1985, water temperatures were cooler than normal across the Indian Ocean.<ref>{{cite report|page=3|author=Darwin Regional Specialised Meteorological Centre|publisher=Bureau of Meteorology|volume=4|number=12|date=December 1985|title=Darwin Tropical Diagnostic Statement|access-date=2015-03-05|url=http://www.bom.gov.au/climate/ntregion/statements/tropical/dtds-198512.pdf|archive-date=2015-04-02|archive-url=https://web.archive.org/web/20150402113542/http://www.bom.gov.au/climate/ntregion/statements/tropical/dtds-198512.pdf|url-status=live}}</ref> However, the [[monsoon]] intensified the following month, allowing for increased [[tropical cyclogenesis]].<ref name="jbom">{{cite report|page=3|author=Darwin Regional Specialised Meteorological Centre|publisher=Bureau of Meteorology|volume=5|number=1|date=January 1986|title=Darwin Tropical Diagnostic Statement|access-date=2015-03-05|url=http://www.bom.gov.au/climate/ntregion/statements/tropical/dtds-198601.pdf|archive-date=2015-04-02|archive-url=https://web.archive.org/web/20150402141346/http://www.bom.gov.au/climate/ntregion/statements/tropical/dtds-198601.pdf|url-status=live}}</ref> There were no [[El Niño]] conditions by March.<ref>{{cite report|page=3|author=Darwin Regional Specialised Meteorological Centre|publisher=Bureau of Meteorology|volume=5|number=3|date=February 1987|title=Darwin Tropical Diagnostic Statement|access-date=2015-03-05|url=http://www.bom.gov.au/climate/ntregion/statements/tropical/dtds-198603.pdf|archive-date=2015-04-02|archive-url=https://web.archive.org/web/20150402093713/http://www.bom.gov.au/climate/ntregion/statements/tropical/dtds-198603.pdf|url-status=live}}</ref>

In addition to the storms tracked by the MFR, the JTWC followed a short-lived tropical storm in September. Classified as Tropical Cyclone 01S, the storm developed on September&nbsp;23 to the east-southeast of [[Diego Garcia]], which is an [[atoll]] in the central Indian Ocean. It failed to intensify beyond peak 1&nbsp;minute winds of {{convert|75|km/h|mph|abbr=on|round=5}}, and after passing south of Diego Garcia, the storm dissipated on September&nbsp;29 south of the [[Seychelles]].<ref name="atcr"/>
{{clear}}

== Systems ==

=== Tropical Depression Alifredy ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Alifredy Dec 23 1985 1200Z.png
|Track=Alifredy 1985 track.png
|Formed=December 23
|Dissipated=December 27
|1-min winds=35
|10-min winds=28
|Pressure=997
}}
On December&nbsp;23, a tropical depression formed in the Mozambique Channel, accompanied by spiral [[rainband]]s toward the center.<ref name="a">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Depression Alifredy, 22–26 December|year=1996|work=National Climatic Data Center|access-date=2015-03-05|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1985_10.NAR|archive-date=2023-09-12|archive-url=https://web.archive.org/web/20230912014814/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1985_10.NAR|url-status=live}}</ref> That day, the system reached peak winds of {{convert|65|km/h|mph|abbr=on|round=5}},<ref name="abt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Alifredy (1985356S20040)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-05|url={{IBTRACS url|id=1985356S20040}}|archive-url=https://web.archive.org/web/20160707124914/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1985356S20040|archive-date=2016-07-07|url-status=live}}</ref> and the Madagascar Meteorological Service named it Alifredy. The storm moved quickly southeastward toward Madagascar. High pressures to the south prevented much development, and Alifredy moved ashore near [[Morondava]] in western Madagascar on December&nbsp;24 at peak intensity. While crossing the island, the storm weakened into a tropical depression. Alifredy emerged into the open Indian Ocean and failed to restrengthen. It became [[extratropical cyclone|extratropical]] and turned southeastward, dissipating on December&nbsp;27 within the [[westerlies]].<ref name="a"/><ref name="abt"/> The JTWC did not track the storm.<ref name="atcr"/> Alifredy had little impacts on Madagascar; [[Morombe]] reported a peak wind gust of {{convert|56|km/h|mph|abbr=on}}.<ref name="a"/>
{{clear}}

=== Moderate Tropical Storm Berobia ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=06S Jan 9 1986 1220Z.png
|Track=Berobia 1986 track.png
|Formed=January 5
|Dissipated=January 10
|1-min winds=50
|10-min winds=45
|Pressure=984
}}
The [[Intertropical Convergence Zone]] (ITCZ) spawned a tropical depression in the northern periphery of the Mozambique Channel on January&nbsp;5, near the [[Comoros]]. Initially still located with the ITCZ, the system tracked south-southwestward, although its motion slowed due to a [[ridge (meteorology)|ridge]] to the south. It passed near [[Juan de Nova Island]] on January&nbsp;6, producing gusts of {{convert|81|km/h|mph|abbr=on}}. By January&nbsp;7, the system began disassociating itself from the ITCZ and it intensified. That night, the Madagascar Meteorological Service named the depression Berobia,<ref name="b">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Depression Berobia, 5–10 January|year=1996|work=National Climatic Data Center|access-date=2015-03-05|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_1.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121857/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_1.NAR|url-status=live}}</ref> which intensified into a moderate tropical storm the next day.<ref name="bbt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Berobia (1986005S15043)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-05|url={{IBTRACS url|id=1986005S15043}}|archive-url=https://web.archive.org/web/20160305205854/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986005S15043|archive-date=2016-03-05|url-status=live}}</ref> Also on January&nbsp;8, the JTWC began classifying the storm as Tropical Cyclone 06S.<ref name="atcr"/> That day, Berobia began moving to the west-northwest, due to the strengthening ridge to the south.<ref name="b"/> On January&nbsp;9, the storm attained peak winds of {{convert|85|km/h|mph|abbr=on|round=5}} according to the MFR; the JTWC estimated a slightly higher 1&nbsp;minute peak of {{convert|95|km/h|mph|abbr=on|round=5}}.<ref name="bbt"/> Late on January&nbsp;9, Berobia made landfall about 125&nbsp;km (75&nbsp;mi) north of [[Beira, Mozambique]], and it dissipated the next day after entering [[Zimbabwe]].<ref name="b"/><ref name="bbt"/> The remnants of Berobia dropped heavy rainfall in northeastern Zimbabwe, with a 24‑hour peak of {{convert|179|mm|in|abbr=on}}.<ref>{{cite report|title=Preliminary Water Resources Assessment for the Limpopo River Basin|author=A. Mhizha|author2=M. Musariri|author3=E. Madamombe|author4=Tererai|publisher=University of Zimbabwe|date=2012-01-23|url=http://www.waternetonline.ihe.nl/challengeprogram/IR29%20Mhizha%20prelim%20water%20res.pdf|format=PDF|access-date=2015-03-05|archive-url=https://web.archive.org/web/20150402100828/http://www.waternetonline.ihe.nl/challengeprogram/IR29%20Mhizha%20prelim%20water%20res.pdf|archive-date=2015-04-02|url-status=live}}</ref>
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=== Severe Tropical Storm Costa ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=STS Costa 1986.jpg
|Track=Costa 1986 track.png
|Formed=January 7
|Dissipated=January 19
|1-min winds=70
|10-min winds=52
|Pressure=976
}}
Tropical Storm Costa was a series of three different tropical depressions within the same broader system that persisted for 12&nbsp;days east of Madagascar, all given the same name. The first circulation formed on January&nbsp;7 between the northeast coast of Madagascar and [[Agaléga]]. Later that day, the Madagascar Meteorological Service named it Costa,<ref name="c">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical System Costa, 7–19 January|year=1996|work=National Climatic Data Center|access-date=2015-03-05|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_4.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121904/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_4.NAR|url-status=live}}</ref> and the JTWC labeled it Tropical Cyclone 05S.<ref name="atcr"/> It moved eastward and later turned to the southeast, passing near Agaléga before weakening while moving into the ITCZ. Another circulation formed to the east of Costa, and the original circulation dissipated on January&nbsp;9. The new center moved to the west-southwest toward [[St. Brandon]], although it was disorganized, dissipating on January&nbsp;11. A third circulation formed on the previous day to the east, becoming a tropical depression with well-organized rainbands. This third system would last the longest, originally moving to the northeast before curving southeastward.<ref name="c"/>

On January&nbsp;12, Costa intensified into a moderate tropical storm. On the next day, the JTWC upgraded it to the equivalent of a minimal hurricane, and the MFR estimated peak winds of {{convert|95|km/h|mph|abbr=on|round=5}}. Costa weakened briefly on January&nbsp;14 while passing about 100&nbsp;km (60&nbsp;mi) east of [[Rodrigues]], although it re-attained its former peak on the next day while accelerating southeastward. Costa thereafter weakened rapidly and moved erratically toward the southwest. By January&nbsp;15, it deteriorated into a minimal tropical storm, and meandered for several days. On January&nbsp;19, Costa dissipated within the flow of the westerlies.<ref name="c"/><ref>{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Costa (1986007S11055)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-05|url={{IBTRACS url|id=1986007S11055}}|archive-url=https://web.archive.org/web/20160305083341/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986007S11055|archive-date=2016-03-05|url-status=live}}</ref>

When Costa formed, it passed near Agaléga, producing wind gusts of {{convert|145|km/h|mph|abbr=on}}. The storm approached St. Brandon twice; on its first passage, Costa produced gusts of {{convert|91|km/h|mph|abbr=on}} during a strong rainband. Later, the storm dropped {{convert|64|mm|in|abbr=on}} of rainfall on Rodrigues while producing gusts of {{convert|107|km/h|mph|abbr=on}}.<ref name="c"/>
{{clear}}

=== Tropical Cyclone Delifina ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Cyclone Delifinina 1986 STS-61-C.jpg
|Track=Delifinina 1986 track.png
|Formed=January 10
|Dissipated=January 19
|1-min winds=110
|10-min winds=72
|Pressure=954
}}
The monsoon was active in early January across the Indian Ocean, spawning what would eventually become Tropical Cyclone Delifina.<ref name="jbom"/> On January&nbsp;7, the JTWC classified the system as Tropical Cyclone 04S to the east-southeast Tropical Storm Costa.<ref name="atcr"/> However, the MFR did not classify it initially due to lack of data. The system had a curved area of [[convection (meteorology)|convection]], and organized enough for MFR to designate it Tropical Storm Delifina on January&nbsp;10.<ref name="d">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Cyclone Delifina, 7–19 January|year=1996|work=National Climatic Data Center|access-date=2015-03-05|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_3.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121857/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_3.NAR|url-status=live}}</ref> On the same day, the JTWC upgraded the storm to the equivalent of a minimal hurricane.<ref name="dbt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Delifina (1986007S07080)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-05|url={{IBTRACS url|id=1986007S07080}}|archive-url=https://web.archive.org/web/20160305204357/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986007S07080|archive-date=2016-03-05|url-status=live}}</ref> The storm moved generally southward, after an initial westward movement. Delifina gradually intensified, becoming a tropical cyclone on January&nbsp;13. By that time, the storm had an [[eye (cyclone)|eye]] in the center of deep organized convection. The MFR estimated peak winds of {{convert|135|km/h|mph|abbr=on|round=5}}, while the JTWC estimated 1&nbsp;minute winds of {{convert|205|km/h|mph|abbr=on|round=5}}. Subsequently, Delifina weakened as it progressed southward. After turning to the southeast, the deteriorating storm turned sharply northwestward between two ridges. Delifina turned back to the east and dissipated on January&nbsp;19 at nearly the same longitude where it formed.<ref name="d"/><ref name="dbt"/>
{{clear}}

=== Intense Tropical Cyclone Erinesta ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Erinesta Feb 3 1986 1115Z.png
|Track=Erinesta 1986 track.png
|Formed=January 29
|Dissipated=February 11
|1-min winds=115
|10-min winds=92
|Pressure=927
}}
Satellite imagery indicated that a tropical disturbance formed on January&nbsp;29 to the southwest of Diego Garcia. It moved westward and slowly organized,<ref name="e"/> becoming a moderate tropical storm on January&nbsp;31.<ref name="ebt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Erinesta (1986029S14069)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-06|url={{IBTRACS url|id=1986029S14069}}|archive-url=https://web.archive.org/web/20160305083300/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986029S14069|archive-date=2016-03-05|url-status=live}}</ref> On the same day, the JTWC classified the storm as Tropical Cyclone 13S,<ref name="atcr"/> and the Mauritius Meteorological Service named it Erinesta. Its track shifted to a slow west-southwest trajectory while intensifying.<ref name="e"/> The JTWC upgraded the storm to the equivalent of a minimal hurricane on February&nbsp;1, and the MFR upgraded Erinesta to tropical cyclone status on the next day.<ref name="ebt"/> On February&nbsp;4, the cyclone attained peak winds, becoming one of the strongest storms in the basin in several decades.<ref name="e"/> The JTWC estimated peak 1&nbsp;minute winds of {{convert|215|km/h|mph|abbr=on|round=5}}, and the MFR estimated peak winds of {{convert|170|km/h|mph|abbr=on|round=5}}.<ref name="ebt"/> Shortly after Erinesta reached peak intensity, it passed within {{convert|20|km|mi|abbr=on}} of [[Tromelin Island]]. The storm curved southward due to an approaching [[trough (meteorology)|trough]], briefly threatening to strike Réunion. However, a ridge built behind the trough, bringing the storm between the east coast of Madagascar and the Mascarene Islands. Erinesta gradually weakened, passing west of Réunion as a severe tropical storm on February&nbsp;7. The storm accelerated to the south-southeast and later became extratropical, dissipating on February&nbsp;11 within the westerlies.<ref name="e"/><ref name="ebt"/>

Passing near Tromelin at peak intensity, Erinesta produced peak wind gusts of {{convert|234|km/h|mph|abbr=on}} before damaging the [[anemometer]], with peak winds estimated as high as {{convert|250|km/h|mph|abbr=on|round=5}}. The high winds damaged every building and scientific instrument on the island.<ref name="e">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Cyclone Erinesta, 29 January-11 February|year=1996|work=National Climatic Data Center|access-date=2015-03-05|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_5.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121903/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_5.NAR|url-status=live}}</ref> The passage of the storm killed Tromelin's entire rabbit population.<ref>{{cite web|title=Iles Eparses|page=110|publisher=Biodiversité et Conservation en Outre-Mer|language=fr|access-date=2015-03-05|url=http://www.uicn.fr/IMG/pdf/08_UICN_2003_Biodiv_OM_-_Iles_Eparses.pdf|archive-url=https://web.archive.org/web/20160304032346/http://www.uicn.fr/IMG/pdf/08_UICN_2003_Biodiv_OM_-_Iles_Eparses.pdf|archive-date=2016-03-04|url-status=live}}</ref> Along the east coast of Madagascar, Erinesta produced {{convert|83|km/h|mph|abbr=on}} wind gusts and 24‑hour rainfall of {{convert|64.8|mm|in|abbr=on}} at [[Toamasina]]. Lastly, the cyclone passed west of Réunion, where ten days of precipitation accumulated to {{convert|1643|mm|in|abbr=on}} at [[Cilaos]], of which {{convert|1017|mm|in|abbr=on}} fell over 24&nbsp;hours.<ref name="e"/> The 24‑hour total there was among the highest on record, surpassing even [[Cyclone Hyacinthe]], the wettest storm on record. In one hour, Erinesta dropped {{convert|70|mm|in|abbr=on}} of rainfall, which only occurs every two and a half years. This helped replenish aquifer levels, after two years of drought conditions.<ref>{{cite report|author=Direction Departemantale de l'Agriculture|publisher=Department de La Reunion|title=La Depression Cyclonique "Erinesta"|year=1986|url=http://www.eaureunion.fr/fileadmin/user_upload/Etudes/ETUDE_00602.PDF|format=PDF|access-date=2015-03-06|archive-date=2015-04-02|archive-url=https://web.archive.org/web/20150402115100/http://www.eaureunion.fr/fileadmin/user_upload/Etudes/ETUDE_00602.PDF|url-status=live}}</ref> The rains caused [[return period|1 in 10 year flooding]] in portions of the island, reaching 30&nbsp;m<sup>3</sup>/s (1,060&nbsp;ft<sup>3</sup>/s) at Ravine Blanche.<ref>{{cite report|access-date=2015-03-06|url=http://www.eaureunion.fr/fileadmin/user_upload/Etudes/ETUDE_00559.PDF|format=PDF|publisher=Department de La Reunion|author=Direction de l'Agriculture et de la Foret|year=1986|title=Annuaire Hydrologique|language=fr|archive-date=2015-04-02|archive-url=https://web.archive.org/web/20150402131405/http://www.eaureunion.fr/fileadmin/user_upload/Etudes/ETUDE_00559.PDF|url-status=live}}</ref> While moving past the island, Erinesta produced peak gusts of {{convert|139|km/h|mph|abbr=on}} in the mountainous interior at [[Plaine des Cafres]].<ref name="e"/> The cyclone also produced very high waves along coastal roads, closing them for four days and damaging guard rails.<ref>{{cite report|title=Reinforced Earth Marine and Dam Structures|access-date=2015-03-05|publisher=Groupe TAI|page=4|url=http://www.reinforcedearth.com.tr/pdf/reinforced_earth-marine_and_dam_structures.pdf|format=PDF|date=|archive-date=2015-04-02|archive-url=https://web.archive.org/web/20150402104147/http://www.reinforcedearth.com.tr/pdf/reinforced_earth-marine_and_dam_structures.pdf|url-status=live}}</ref>
{{clear}}

=== Moderate Tropical Storm Filomena ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Filomena Feb 6 1986 0901Z.png
|Track=Filomena 1986 track.png
|Formed=February 5
|Dissipated=February 12
|1-min winds=55
|10-min winds=35
|Pressure=991
}}
In early February, an area of disturbed weather persisted around Diego Garcia, although lack of satellite imagery made it difficult to track the system at first.<ref name="f">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Depression Filomena, 5–12 February|year=1996|work=National Climatic Data Center|access-date=2015-03-02|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_6.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121859/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_6.NAR|url-status=live}}</ref> On February&nbsp;6, satellite images indicated that a tropical storm formed,<ref name="fbt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Filomena (1986036S10082)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-01|url={{IBTRACS url|id=1986036S10082}}|archive-url=https://web.archive.org/web/20160305204345/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986036S10082|archive-date=2016-03-05|url-status=live}}</ref> given the name Filomena by the Mauritius Meteorological Service.<ref name="f"/> Also on February&nbsp;6, the JTWC classified it as Tropical Cyclone 14S.<ref name="atcr"/> Initially the storm moved to the west, although Filomena turned southeastward into an area of low pressure.<ref name="f"/> The storm never intensified beyond winds of {{convert|65|km/h|mph|abbr=on|round=5}} according to the MFR. However, the JTWC estimated 1&nbsp;minute winds of {{convert|100|km/h|mph|abbr=on|round=5}}.<ref name="fbt"/> Filomena gradually weakened as it progress southward. On February&nbsp;11, the system turned westward and later northwest due to a ridge to the south, having weakened into a tropical depression. Filomena dissipated on the next day.<ref name="f"/><ref name="fbt"/>
{{Clear}}

=== Severe Tropical Storm Gista ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Gista Feb 23 1986 1239Z.png
|Track=Gista 1986 track.png
|Formed=February 18
|Dissipated=February 25
|1-min winds=85
|10-min winds=52
|Pressure=976
}}
On February&nbsp;18, a circulation formed in the Mozambique Channel, based on satellite imagery. That day, it developed into Moderate Tropical Storm Gista,<ref name="g">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Depression Gista, 18–25 February|year=1996|work=National Climatic Data Center|access-date=2015-03-05|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_7.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121858/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_7.NAR|url-status=live}}</ref><ref name="gbt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Gista (1986049S18043)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-05|url={{IBTRACS url|id=1986049S18043}}|archive-url=https://web.archive.org/web/20160305083202/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986049S18043|archive-date=2016-03-05|url-status=live}}</ref> Early on February&nbsp;19, the JTWC classified it as Tropical Cyclone 19S.<ref name="atcr"/> Gista moved generally southward, initially moving to the southeast toward western Madagascar and later curving to the southwest, bringing it within 100&nbsp;km (60&nbsp;mi) of the coast. The storm gradually intensified while moving away from the country, reaching peak 10&nbsp;minute winds of {{convert|95|km/h|mph|abbr=on|round=5}} on January&nbsp;21 about 120&nbsp;km (75&nbsp;mi) east of [[Europa Island]]. According to the MFR, Gista became extratropical that night, although the JTWC continued tracking it for several more days. According to the JTWC, Gista intensified to the equivalent of a minimal hurricane on February&nbsp;22 to the southwest of Madagascar, and the next day reached peak 1&nbsp;minute winds of {{convert|160|km/h|mph|abbr=on|round=5}}. Gista accelerated to the southeast and dissipated late on February&nbsp;24 in the westerlies.<ref name="g"/><ref name="gbt"/>

While Gista was moving along the west coast of Madagascar, it produced peak wind gusts of {{convert|82|km/h|mph|abbr=on}} at [[Maintirano]]. It later produced wind gusts of {{convert|72|km/h|mph|abbr=on}} on Europa Island.<ref name="g"/>
{{Clear}}

=== Tropical Cyclone Honorinina ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Honorinina Mar 13 1986 1111Z.png
|Track=Honorinina 1986 track.png
|Formed=March 7
|Dissipated=March 23
|1-min winds=110
|10-min winds=82
|Pressure=941
}}
{{main|Cyclone Honorinina}}
Tropical Storm Honorinina formed on March&nbsp;9 to the south of [[Diego Garcia]]. It moved generally to the west-southwest due to a [[ridge (meteorology)|ridge]] to the south, gradually intensifying. On March&nbsp;12, the MFR upgraded Honorinina to [[Tropical cyclone scales#South-West Indian Ocean|tropical cyclone status]], which is the equivalent of a minimal hurricane. On the next day, the cyclone attained [[maximum sustained wind]]s of {{convert|150|km/h|mph|abbr=on|round=5}} while in the vicinity of Tromelin Island, although the JTWC estimated peak 1&nbsp;minute winds of {{convert|205|km/h|mph|abbr=on|round=5}}. Honorinina weakened subsequently before making [[landfall]] about 40&nbsp;km (25&nbsp;mi) north of [[Toamasina]], Madagascar with winds of {{convert|135|km/h|mph|abbr=on|round=5}}. The storm weakened further over land, moving southwestward across the country. It emerged into the [[Mozambique Channel]] and became [[extratropical cyclone|extratropical]] on March&nbsp;18. Honorinina turned to the southeast, dissipating on March&nbsp;23.<ref name="h">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Cyclone Honorinina, 7–23 March|year=1996|work=National Climatic Data Center|access-date=2015-02-17|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_8.NAR|archive-date=2022-04-16|archive-url=https://web.archive.org/web/20220416123043/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_8.NAR|url-status=live}}</ref><ref>{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Honorinina (1986067S11080)|publisher=Bulletin of the American Meteorological Society|access-date=2015-02-17|url={{IBTRACS url|id=1986067S11080}}|archive-url=https://web.archive.org/web/20160305143643/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986067S11080|archive-date=2016-03-05|url-status=live}}</ref>

Early in its duration, the storm produced gusty winds along [[St. Brandon]], and it later brought gusts of {{convert|158|km/h|mph|abbr=on}} on Tromelin Island.<ref name="h"/> However, effects were worst in Madagascar, especially in Toamasina near where the storm made landfall. Damage spread along 800&nbsp;km (500&nbsp;mi) of the coastline and reached 100&nbsp;km (60&nbsp;mi) inland from the landfall point, with many towns severely affected. In Toamasina, the cyclone damaged the main port, the airport, and several warehouses, resulting in $17&nbsp;million (1986&nbsp;[[United States dollar|USD]]) of lost inventory.<ref name="usaid">{{cite web|publisher=United States Agency for International Development|title=Disaster Case Report: Madagascar – Cyclone|date=1986-03-15|access-date=2015-02-18|url=http://pdf.usaid.gov/pdf_docs/pbaab374.pdf|archive-date=2015-02-21|archive-url=https://web.archive.org/web/20150221013410/http://pdf.usaid.gov/pdf_docs/pbaab374.pdf|url-status=live}}</ref><ref name="wb2">{{cite report|url=http://www-wds.worldbank.org/servlet/WDSContentServer/IW3P/IB/1992/05/11/000009265_3960925213356/Rendered/PDF/multi_page.pdf|format=PDF|access-date=2015-02-20|publisher=World Bank|title=Cyclone Rehabilitation Project|date=1992-05-11|archive-date=2016-06-11|archive-url=https://web.archive.org/web/20160611165133/http://www-wds.worldbank.org/servlet/WDSContentServer/IW3P/IB/1992/05/11/000009265_3960925213356/Rendered/PDF/multi_page.pdf|url-status=live}}</ref> Thousands of houses were damaged, leaving 83,885&nbsp;people homeless; a housing program earlier set up after [[Cyclone Kamisy]] in 1984 was extended to help storm victims after Honorinina.<ref name="usaid"/> Nationwide, the cyclone killed 99&nbsp;people and caused $150&nbsp;million (1986&nbsp;USD) in damage.<ref name="usaid"/><ref>{{Cite web|url=http://www.emdat.be/|access-date=2015-02-20|author=Centre for Research on the Epidemiology of Disasters|publisher=Université catholique de Louvain|title=EM-DAT: The OFDA/CRED International Disaster Database|archive-date=2014-02-15|archive-url=https://web.archive.org/web/20140215235623/http://www.emdat.be/|url-status=live}}</ref>
{{Clear}}

=== Moderate Tropical Storm Iarima ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Iarima Mar 13 1986 0929Z.png
|Track=Iarima 1986 track.png
|Formed=March 13
|Dissipated=March 18
|1-min winds=35
|10-min winds=35
|Pressure=991
}}
While Honorinina was intensifying and moving toward Madagascar, another system was forming on March&nbsp;13 south-southeast of Diego Garcia.<ref name="i">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Depression Iarima, 11–18 March|year=1996|work=National Climatic Data Center|access-date=2015-03-02|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_9.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121858/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_9.NAR|url-status=live}}</ref> At 06:00&nbsp;[[Coordinated Universal Time|UTC]] that day, a tropical storm formed,<ref name="ibt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Iarima (1986070S13082)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-01|url={{IBTRACS url|id=1986070S13082}}|archive-url=https://web.archive.org/web/20160305082623/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986070S13082|archive-date=2016-03-05|url-status=live}}</ref> although it was not named Iarima until the next day.<ref name="i"/> Also on March&nbsp;13, the JTWC began classifying the storm as Tropical Cyclone 26S.<ref name="atcr"/> Iarima initially moved southwestward, failing to intensify beyond winds of {{convert|65|km/h|mph|abbr=on|round=5}}.<ref name="ibt"/> On March&nbsp;15, the storm turned and accelerated to the southeast after an anticyclone formed between Iarima and Honorinina. It subsequently weakened, dissipating on March&nbsp;18 while approaching 90°&nbsp;E.<ref name="i"/><ref name="ibt"/>
{{clear}}

=== Tropical Cyclone Jefotra ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Jefotra Mar 29 1986 0959Z.png
|Track=Jefotra 1986 track.png
|Formed=March 27
|Dissipated=April 5
|1-min winds=115
|10-min winds=72
|Pressure=954
}}
An area of low pressure persisted in the northeast portion of the basin toward the end of March. On March&nbsp;27, a tropical depression formed to the southeast of Diego Garcia. The system moved west-southwestward, quickly intensifying into a tropical storm. The Mauritius Meteorological Center named the storm Jefotra,<ref name="j">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Cyclone Jefotra, 25 March-5 April|year=1996|work=National Climatic Data Center|access-date=2015-03-05|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_10.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121859/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_10.NAR|url-status=live}}</ref> while the JTWC designated it as Tropical Cyclone 27S.<ref name="atcr"/> On March&nbsp;28, the JTWC upgraded Jefotra to the equivalent of a minimal hurricane, and on the next day, the MFR upgraded the storm to tropical cyclone status. On March&nbsp;29, Jefotra attained its peak intensity; the JTWC estimated 1&nbsp;minute winds of {{convert|195|km/h|mph|abbr=on|round=5}}, and the MFR estimated 10&nbsp;minute winds of {{convert|135|km/h|mph|abbr=on|round=5}}. By that time, the motion shifted more to the southwest, bringing it 400&nbsp;km (250&nbsp;mi) east of Rodrigues; winds on the island remained less than {{convert|74|km/h|mph|abbr=on}}. The storm gradually weakened to tropical depression status by April&nbsp;2. That day, an approaching cold front turned Jefotra to the southeast, and the storm became extratropical. On April&nbsp;5, the circulation dissipated within the cold front.<ref name="j"/><ref name="jbt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Jefotra (1986085S13091)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-05|url={{IBTRACS url|id=1986085S13091}}|archive-url=https://web.archive.org/web/20151002163602/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986085S13091|archive-date=2015-10-02|url-status=live}}</ref>
{{clear}}

=== Severe Tropical Storm Alison–Krisostoma ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Alison Apr 11 1986 0919Z.png
|Track=Alison-Krisostoma 1986 track.png
|Formed=April 10 ([[1985–86 Australian region cyclone season#Severe Tropical Cyclone Alison-Krisostoma|entered basin]])
|Dissipated=April 13 (exited basin)
|1-min winds=95
|10-min winds=52
|Pressure=974
}}
A tropical low formed in the Australian basin on April&nbsp;4 to the southwest of Sumatra. It moved to the west-southwest without much development, steered by a ridge to the south. It attained gale-force winds on April&nbsp;7 and was named Alison by the [[Bureau of Meteorology]] in Australia (BoM). On the next day, the storm passed just north of the Cocos Islands, and the BoM upgraded Alison to the equivalent of a tropical cyclone.<ref>{{cite web|publisher=Bureau of Meteorology|title=Tropical Cyclone Alison|access-date=2015-03-02|url=http://www.bom.gov.au/cyclone/history/pdf/alison86.pdf|archive-date=2015-09-24|archive-url=https://web.archive.org/web/20150924020015/http://www.bom.gov.au/cyclone/history/pdf/alison86.pdf|url-status=live}}</ref> The JTWC also classified it as Tropical Cyclone 28S.<ref name="atcr"/> The storm crossed 90°&nbsp;E into the south-west Indian Ocean on April&nbsp;10, and the Mauritius Meteorological Service renamed it Krisostoma.<ref>{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Hurricane Alison, 4–13 April|year=1996|work=National Climatic Data Center|access-date=2015-02-17|url=http://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID218/DATA/TROPIC/SWP_NAR/1986_15|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121138/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID218/DATA/TROPIC/SWP_NAR/1986_15|url-status=live}}</ref> The MFR estimated peak winds of {{convert|95|km/h|mph|abbr=on|round=5}}, much less than the JTWC 1&nbsp;minute estimate of {{convert|160|km/h|mph|abbr=on|round=5}}.<ref name="kbt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Alison:Alison_Kriso:Krisostoma (1986095S11105)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-02|url={{IBTRACS url|id=1986095S11105}}|archive-url=https://web.archive.org/web/20150930152927/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986095S11105|archive-date=2015-09-30|url-status=live}}</ref> An eastward area of low pressure turned the storm to the southeast, crossing back into the Australian basin on April&nbsp;13. On the next day, the storm dissipated. The JTWC analyzed the end of Krisostoma as turning back to the west-southwest without exiting the south-west Indian Ocean.<ref name="kbt"/>
{{Clear}}

=== Tropical Cyclone Billy-Lila ===
{{Infobox Hurricane Small
|Basin=SWI
|Image=Billy-Lila May 10 1986 0911Z.png
|Track=Billy 1986 track.png
|Formed=May 9 ([[1985–86 Australian region cyclone season#Severe Tropical Cyclone Billy-Lila|entered basin]])
|Dissipated=May 10 (exited basin)
|1-min winds=90
|10-min winds=72
|Pressure=950
}}
On May&nbsp;4, a monsoonal low developed southwest of Sumatra in the Australian basin. It moved to the southeast and intensified into a tropical storm on May&nbsp;5, given the name Billy.<ref name="billy"/> That day, the JTWC classified the system as Tropical Cyclone 32S.<ref name="atcr">{{cite report|publisher=Joint Typhoon Warning Center|page=152|title=Annual Tropical Cyclone Report|access-date=2015-02-17|url=http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/atcr/1986atcr.pdf|format=PDF|date=|archive-date=2012-09-15|archive-url=https://web.archive.org/web/20120915165323/http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/atcr/1992atcr.pdf|url-status=dead}}</ref> The storm turned to the southwest due to a ridge to the south, crossing 90°&nbsp;E into the south-west Indian Ocean on May&nbsp;9.<ref name="billy">{{cite web|publisher=Australian Bureau of Meteorology|title=Severe Tropical Cyclone Billy|access-date=2015-03-01|url=http://www.bom.gov.au/cyclone/history/pdf/billy86.pdf|archive-date=2015-09-24|archive-url=https://web.archive.org/web/20150924020107/http://www.bom.gov.au/cyclone/history/pdf/billy86.pdf|url-status=live}}</ref> At that time, the Mauritius Meteorological Service renamed the storm Lila. The storm curved more to the south due to an approaching trough,<ref name="l">{{cite report|series=Global tropical/extratropical cyclone climatic atlas|title=Tropical Cyclone Billy/Lila, 4–15 May|year=1996|work=National Climatic Data Center|access-date=2015-02-17|url=https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_11.NAR|archive-date=2022-04-17|archive-url=https://web.archive.org/web/20220417121902/https://webapp1.dlib.indiana.edu/virtual_disk_library/index.cgi/4274123/FID1030/DATA/TROPIC/SWI_NAR/1986_11.NAR|url-status=live}}</ref> Early on May&nbsp;10, the MFR estimated peak winds of {{convert|135|km/h|mph|abbr=on|round=5}}, and the JTWC estimated peak 1&nbsp;minute winds of {{convert|165|km/h|mph|abbr=on|round=5}}.<ref name="lbt">{{cite report|author=Kenneth R. Knapp|author2=Michael C. Kruk|author3=David H. Levinson|author4=Howard J. Diamond|author5=Charles J. Neumann|year=2010|work=The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data|title=1986 Billy-Lila:Billy_Lila:Lila (1986124S05090)|publisher=Bulletin of the American Meteorological Society|access-date=2015-03-01|url={{IBTRACS url|id=1986124S05090}}|archive-url=https://web.archive.org/web/20150930185445/http://atms.unca.edu/ibtracs/ibtracs_v03r04/browse-ibtracs/index.php?name=v03r04-1986124S05090|archive-date=2015-09-30|url-status=live}}</ref> Shortly thereafter, Lila crossed 90°&nbsp;E back into the Australian basin, where it was renamed Billy.<ref name="l"/> The storm intensified further before weakening steadily due to wind shear, all while accelerating to the southeast. The circulation eventually crossed the [[Western Australian]] coast near [[Geraldton, Western Australia|Geraldton]] on May&nbsp;14. Moving across southwestern Australia, Billy dissipated on May&nbsp;15 in the [[Great Australian Bight]] off [[South Australia]].<ref name="billy"/><ref name="lbt"/>

{{clear}}

== See also ==
* Atlantic hurricane seasons: [[1985 Atlantic hurricane season|1985]], [[1986 Atlantic hurricane season|1986]]
* Eastern Pacific hurricane seasons: [[1985 Pacific hurricane season|1985]], [[1986 Pacific hurricane season|1986]]
* Western Pacific typhoon seasons: [[1985 Pacific typhoon season|1985]], [[1986 Pacific typhoon season|1986]]
* North Indian Ocean cyclone seasons: [[1985 North Indian Ocean cyclone season|1985]], [[1986 North Indian Ocean cyclone season|1986]]

== Notes ==
{{Reflist|group=nb}}

== References ==
{{reflist|2}}

{{Tropical cyclone season|1985|split-year=y}}
{{TC Decades|Year=1980|basin=South-West Indian Ocean|type=cyclone|shem=yes}}

{{DEFAULTSORT:1985-86 South-West Indian Ocean cyclone season}}
[[Category:1985–86 South-West Indian Ocean cyclone season| ]]
[[Category:South-West Indian Ocean cyclone seasons]]
[[Category:Tropical cyclones in 1985]]
[[Category:Tropical cyclones in 1986]]
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