1980–81 South-West Indian Ocean cyclone season

Moderate tropical storm (MFR)
Tropical storm (SSHWS)
	<img src="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Bettina_Dec_1_1980_0433Z.png/150px-Bettina_Dec_1_1980_0433Z.png" decoding="async" width="150" height="172" class="mw-file-element" data-file-width="382" data-file-height="437"> <img src="//upload.wikimedia.org/wikipedia/commons/thumb/0/0e/Bettina_1980_track.png/150px-Bettina_1980_track.png" decoding="async" width="150" height="93" class="mw-file-element" data-file-width="1024" data-file-height="633">
Duration	November 22 – December 1
Peak intensity	85 km/h (50 mph) (10-min);;

Tropical cyclone (MFR)
Category 3 tropical cyclone (SSHWS)
	<img src="//upload.wikimedia.org/wikipedia/commons/thumb/e/ef/Adelaide_Nov_8_1980_0121Z.png/150px-Adelaide_Nov_8_1980_0121Z.png" decoding="async" width="150" height="166" class="mw-file-element" data-file-width="410" data-file-height="453"> <img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/49/Alice-Adelaide_1980_track.png/150px-Alice-Adelaide_1980_track.png" decoding="async" width="150" height="93" class="mw-file-element" data-file-width="1024" data-file-height="633">
Duration	November 3 – November 14
Peak intensity	120 km/h (75 mph) (10-min);; 940 hPa (mbar)

1980–81 South-West Indian Ocean cyclone season
1980–81 South-West Indian Ocean cyclone season
	Season summary map
Seasonal boundaries
First system formed	November 8, 1980
Last system dissipated	May 4, 1981
Strongest storm
Name	Florine
• Maximum winds	225 km/h (140 mph); (10-minute sustained)
• Lowest pressure	935 hPa (mbar)
Seasonal statistics
Total depressions	12
Total storms	12
Tropical cyclones	3
Intense tropical cyclones	2
Total fatalities	Unknown
Total damage	Unknown
Related articles
	1980–81 Australian region cyclone season; 1980–81 South Pacific cyclone season;
	South-West Indian Ocean tropical cyclone seasons; 1978–79, 1979–80, 1980–81, 1981–82, 1982–83

The 1980–81 South-West Indian Ocean cyclone season was an average cyclone season.

Season summary edit

Systems edit

Intense Tropical Cyclone Alice–Adelaide edit

On November 3, a low-pressure area developed off the southwest coast of Sumatra in the Australian basin. The BoM upgraded the low to Tropical Cyclone Alice two days later, which was intensifying while moving west-southwestward, steered by the subtropical ridge to its south. Alice attained a peak intensity of 180 km/h (110 mph) in the Australian basin on November 7. While in the region, the cyclone's high waves capsized two boats. The crew of the Sing Long No. 21 escaped in two life rafts; a freighter rescued one raft, but the other was lost, with 12 crew members aboard.^[1]

Cyclone Alice crossed 90º E on November 9, and 85º E a day later,^[1] whereupon the MMS renamed the storm as Adelaide,^[2] estimating winds of at least 120 km/h (75 mph). The JTWC estimated maximum sustained winds of 205 km/h (127 mph) at that time. Adelaide soon began a weakening trend, falling below tropical cyclone status on November 11. A day later, the storm turned to the west-northwest, steered by a ridge to the south. Adelaide weakened to a tropical depression on November 13, and was no longer classifiable a tropical cyclone by a day later.^[3]^[4]^[5]

Moderate Tropical Storm Bettina edit

Bettina formed on November 22, over the central Indian Ocean. It moved south-southwestward and reached a peak intensity of 50 knots (58 mph; 93 km/h) on November 26. It made landfall as a tropical storm over Mozambique and weakened shortly after on December 1.

Tropical Cyclone Bert–Christelle edit

Tropical cyclone (MFR)
Category 1 tropical cyclone (SSHWS)

Duration	November 24 – December 9
Peak intensity	140 km/h (85 mph) (10-min); 965 hPa (mbar)

Formed on November 24 over the open Indian Ocean it moved in a mostly southwest direction, though it did curve a few times. It reached a peak intensity of 80 knots (92 mph; 150 km/h) and a pressure of 965 hectopascals (28.50 inHg) on November 29. Christelle made landfall on Madagascar on December 9 as a tropical depression.

Moderate Tropical Storm Diana edit

Moderate tropical storm (MFR)
Tropical storm (SSHWS)

Duration	December 17 – December 19
Peak intensity	65 km/h (40 mph) (10-min);

Diana existed from December 17 to December 19.

Moderate Tropical Storm Edwige edit

Moderate tropical storm (MFR)
Tropical storm (SSHWS)

Duration	December 28 – January 1
Peak intensity	65 km/h (40 mph) (10-min);

Edwige brushed Madagascar.

Very Intense Tropical Cyclone Florine edit

Very intense tropical cyclone (MFR)
Category 3 tropical cyclone (SSHWS)

Duration	January 3 – January 11
Peak intensity	220 km/h (140 mph) (10-min); 935 hPa (mbar)

Toward the beginning of January, the ITCZ was active to the northeast of Madagascar, spawning a circulation east of Agalega that became a depression on January 3. On the next day, the system was named Florine. Steered between a ridge to its northwest and northeast, the system moved erratically until January 5, when Florine began a steady movement to the south and later southwest. The change in trajectory was because the ridge to Florine's northeast had weakened. On January 6, the intensifying storm passed just west of St. Brandon, where a station recorded sustained winds of 115 km/h (71 mph) and gusts of 148 km/h (92 mph). A day later, the outer eyewall of Florine moved across Réunion island, while the center of the eye passed 25 km east of Sainte-Rose. Roland Garros Airport recorded a minimum pressure of 935 mbar (27.6 inHg), the lowest on the island. A landfall was spared due to a shift in trajectory to the south-southeast caused by a passing cold front.^[6] Also around this time, the cyclone reached its peak intensity according to the JTWC; the agency estimated peak winds of 195 km/h (121 mph), based on a Dvorak rating of 5.5.^[7]^[8] The MFR estimated peak 10 minute winds of 220 km/h (140 mph).^[6] Florine weakened as it accelerated ahead of a polar trough, and was no classifiable as a tropical cyclone on January 10. The remnants passed west of Île Amsterdam on the next day and continued southeastward.^[6]^[7]

Florine's close passage to Réunion caused injuries to two people. The high winds, peaking at 234 km/h (145 mph) at Plaine des Cafres, affected the island alongside heavy rainfall. Precipitation totals ranged from 100 mm (3.9 in) near the coast to 1,161 mm (45.7 in) at Foc-Foc. High tides reached 5.2 m (17 ft) at the coast in La Possession. Cyclone Florine destroyed crops and 95 houses. It caused injuries to two people and left around 500 people homeless. The storm knocked down 2000 phone lines and caused disruptions to the power network. Cilaos and Salazie became isolated during the storm, requiring assistance by helicopter. In nearby Mauritius, winds peaked at 137 km/h (85 mph).^[6]

Moderate Tropical Storm Gaelle edit

Moderate tropical storm (MFR)
Tropical storm (SSHWS)

Duration	January 14 – January 18
Peak intensity	75 km/h (45 mph) (10-min);

Gaelle existed from January 14 to January 18.

Moderate Tropical Storm Helyette edit

Moderate tropical storm (MFR)
Tropical storm (SSHWS)

Duration	January 28 – February 6
Peak intensity	75 km/h (45 mph) (10-min);

On January 31, Tropical Depression Helyette passed north of Rodrigues, and the next day moved over Mauritius and just southeast of Réunion. The highest wind gust was 121 km/h (75 mph) at Fort William on Mauritius. Helyette made landfall in Madagascar.^[9]

Severe Tropical Storm Iadine edit

Severe tropical storm (MFR)
Tropical storm (SSHWS)

Duration	February 16 – February 25
Peak intensity	95 km/h (60 mph) (10-min);

Iadine also made landfall in Madagascar.

Severe Tropical Storm Johanne edit

Severe tropical storm (MFR)
Category 1 tropical cyclone (SSHWS)

Duration	March 1 – March 11
Peak intensity	110 km/h (70 mph) (10-min);

Johanne existed from March 1 to March 11. On March 6, Tropical Storm Johanne passed between Réunion and Mauritius while passing southeastward, with respective island rainfall totals of 316 and 260 mm (12.4 and 10.2 in). The highest wind gust was 124 km/h (77 mph) at Mon Desert Alma on Mauritius.^[10]

Moderate Tropical Storm Klara edit

Moderate tropical storm (MFR)
Tropical storm (SSHWS)

Duration	March 28 – April 8
Peak intensity	75 km/h (45 mph) (10-min);

Klara existed from March 28 to April 8.

Moderate Tropical Storm Lisa edit

Moderate tropical storm (MFR)
Tropical storm (SSHWS)

Duration	April 6 – April 16
Peak intensity	75 km/h (45 mph) (10-min);

Lisa existed from April 6 to April 16.

For several days, Lisa looped to the north of the Mascarene Islands, coming within 200 km (120 mi) of Mauritius on April 9. For several the storm dropped rainfall on the islands, reaching 398 mm (15.7 in) in Mauritius and 445 mm (17.5 in) on Réunion. Flooding caused road damage in the latter island.^[11]

References edit

^ ^a ^b Tropical Cyclone Alice (Report). Australian Bureau of Meteorology. Retrieved November 9, 2018.
^ La Météorlogie, Service de la Réunion. La Saison Cyclonique 1980-1981 A Madagascar (PDF). Madagascar: Revue de Géographie (Report) (in French). Vol. 39. pp. 137–139. Retrieved November 9, 2018.
^ Donnes de Bemany (Report). Météo-France. Archived from the original on January 30, 2005. Retrieved November 9, 2018.
^ Kenneth R. Knapp; Michael C. Kruk; David H. Levinson; Howard J. Diamond; Charles J. Neumann (2010). 1980 Adelaide (1980308S05102). The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data (Report). Bulletin of the American Meteorological Society. Archived from the original on November 10, 2018. Retrieved November 9, 2018.
^ Tropical Cyclone Adelaide, 9–14 November. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved November 9, 2018.
^ ^a ^b ^c ^d Tropical Cyclone Florine 4–10 January. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved November 20, 2016.
^ ^a ^b Kenneth R. Knapp; Michael C. Kruk; David H. Levinson; Howard J. Diamond; Charles J. Neumann (2010). 1981 Florine (1981003S11059). The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data (Report). Bulletin of the American Meteorological Society. Archived from the original on July 7, 2016. Retrieved November 20, 2016.
^ John W. Diercks; Robert C. Weir; Mary K. Kopper. Forecast Verification and Reconnaissance Data for Southern Hemisphere Tropical Cyclones (July 1980 through June 1982) (PDF) (Report). Tech Note. Vol. 82–1. Joint Typhoon Warning Center. Archived from the original on March 4, 2016. Retrieved November 20, 2016.
^ Tropical Cyclone Helyette, 28 January-4 February. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved February 2, 2019.
^ Tropical Depression Johanne, 1–10 March. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved February 2, 2019.
^ Tropical Depression Lisa, 6–14 April. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved February 2, 2019.

[abom-1] Tropical Cyclone Alice (Report). Australian Bureau of Meteorology. Retrieved November 9, 2018.

[ss-2] La Météorlogie, Service de la Réunion. La Saison Cyclonique 1980-1981 A Madagascar (PDF). Madagascar: Revue de Géographie (Report) (in French). Vol. 39. pp. 137–139. Retrieved November 9, 2018.

[amf-3] Donnes de Bemany (Report). Météo-France. Archived from the original on January 30, 2005. Retrieved November 9, 2018.

[4] Kenneth R. Knapp; Michael C. Kruk; David H. Levinson; Howard J. Diamond; Charles J. Neumann (2010). 1980 Adelaide (1980308S05102). The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data (Report). Bulletin of the American Meteorological Society. Archived from the original on November 10, 2018. Retrieved November 9, 2018.

[5] Tropical Cyclone Adelaide, 9–14 November. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved November 9, 2018.

[f-6] Tropical Cyclone Florine 4–10 January. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved November 20, 2016.

[fbt-7] Kenneth R. Knapp; Michael C. Kruk; David H. Levinson; Howard J. Diamond; Charles J. Neumann (2010). 1981 Florine (1981003S11059). The International Best Track Archive for Climate Stewardship (IBTrACS): Unifying tropical cyclone best track data (Report). Bulletin of the American Meteorological Society. Archived from the original on July 7, 2016. Retrieved November 20, 2016.

[jtwc-8] John W. Diercks; Robert C. Weir; Mary K. Kopper. Forecast Verification and Reconnaissance Data for Southern Hemisphere Tropical Cyclones (July 1980 through June 1982) (PDF) (Report). Tech Note. Vol. 82–1. Joint Typhoon Warning Center. Archived from the original on March 4, 2016. Retrieved November 20, 2016.

[9] Tropical Cyclone Helyette, 28 January-4 February. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved February 2, 2019.

[10] Tropical Depression Johanne, 1–10 March. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved February 2, 2019.

[11] Tropical Depression Lisa, 6–14 April. National Climatic Data Center (Report). Global tropical/extratropical cyclone climatic atlas. 1996. Retrieved February 2, 2019.

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