Cyclone Herold

Intense Tropical Cyclone Herold was the first major tropical cyclone worldwide in 2020. Herold was the tenth zone of disturbed weather, ninth depression, eighth moderate tropical storm, sixth severe tropical storm, fifth tropical cyclone, and second intense tropical cyclone of the slightly above-average 2019–20 South-West Indian Ocean cyclone season. Herold formed on 13 March from a disorganized area of low pressure near Tromelin Island.[1]

Not to be confused with Cyclone Harold, another tropical cyclone that affected Oceania less than a month after.
Tropical Cyclone Herold
Intense tropical cyclone (SWIO scale)
Category 3 tropical cyclone (SSHWS)
Herold at peak intensity on 17 March
Formed12 March (12 March) 2020
Dissipated20 March (20 March) 2020
Highest winds10-minute sustained: 175 km/h (110 mph)
1-minute sustained: 185 km/h (115 mph)
Lowest pressure957 hPa (mbar); 28.26 inHg
Fatalities5 total
DamageNone
Areas affectedMadagascar, Tromelin Island, Mauritius, Rodrigues
Part of the 2019–20 South-West Indian Ocean cyclone season

When Herold reached Madagascar, it caused five deaths and unknown damage. Thousands of homes were flooded in the northeastern part. Maroantsetra got the worst of Herold, with all five deaths it caused coming from there.

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

Early in March 2020, an area of low pressure existed near Tromelin Island, but it dissipated on 4 March. It unexpectedly regenerated the next day near the Mascarene Islands. Météo France predicted it would strengthen into a tropical depression by the end of the week.[1] Over the next two weeks, it gradually gained convection,[2] until on 13 March, Zone of Disturbed Weather 10 formed northwest of Madagascar. The next day, the JTWC and MFR upgraded it to a tropical depression.[3] Late on 14 March, 10 reached moderate tropical storm intensity and was named Herold. The JTWC began tracking it as Tropical Cyclone 22S. Herold began to undergo slow intensification. At 18:00 UTC on 15 March, the cyclone was designated Tropical Cyclone Herold. Late on March 17, Herold reached its peak intensity as an Intense tropical cyclone, and the JTWC classified it as a Category 3-equivalent tropical cyclone. As this happened, Herold rapidly moved southeast,[4] Herold's peak intensity was short-lived. On 18 March, Herold began rapidly weakening. Later that day, Herold became extratropical. Finally, on 20 March, Herold dissipated entirely.[5]

Preparations

Madagascar

The first alert, a green alert (issued two to five days before the storm's potential impact[6]), was issued on March 13 by Météo Madagascar for the areas in northeastern Madagascar.[7] The next day, the alert was upgraded to a yellow alert (issued one to two days before storm, storm is going to be damaging area but it has not truly happened yet[6]).

Mascarene Islands

On 18 March, a class four cyclone warning was issued for Rodrigues.[8]

Impact

Madagascar
Herold stalling near the coast of Madagascar on 14 March

Heavy rain was recorded in northeastern Madagascar on 13 March.[9] 95 mm (3.7 inches) fell on Sambava that same day. Intense flooding occurred in the Ankavanana River, which threatened more than 1000 people. Five people were killed in the Sava Region. Flooding impacted more than 100 schools. Homes were swept away in areas near Maroantsetra.[10] Near the Andranofotsy River, people were most affected. By 17 March, though, the water level had decreased a fair amount in the community.[11][12] That day, the water level on land rose to 2 meters (6 feet). 13 of 20 municipalities in the Maroantsetra district were underwater and 28 houses had been destroyed in the town of Mahalevona.[12] In Maroantsetra, 104 homes were affected by the storm surge. A school in Anjanazana was found with puddles of mud in its classrooms.[13] The effects of Herold didn't end until the cyclone alerts were lifted on 17 March for the entire island.[14] 911 homes were flooded. 178 huts were damaged, and 127 residencies were destroyed in Madagascar.[15] In Maroantsetra, 79 classrooms were damaged, and 24 were damaged in Sainte-Marie.[16]

Mascarene Islands

In the Mascarene Islands, maximum sustained winds of 185 km/h (115 mph) was recorded.[17] When Herold passed in between the islands of Mauritius and Rodrigues on 17 March, it made schools close and caused eighty people to seek refuge in accommodation centers. In the islands, damage was minimal. In most areas, it was limited to downed trees and power outages. However, a gust of 130 km/h (81 mph) was recorded in Sir Gaëtan Duval Airport. Maximum rainfall was no more than 29 mm (1.1 inches).[10][18] Herold also briefly passed over Réunion. There was no known damage there.[19]

gollark: It *does* also function as a cool kids' club.
gollark: Yes. All horses must DIE.
gollark: I'm *technically* there due to my trusted user status, but I never read it.
gollark: I mean, the idea is to stop people getting information on doing wildly unsafe things randomly, you can probably ask for *safety* advice elsewhere.
gollark: If you're going to be immensely stupid, at least use correct grammar and spelling when doing it.

See also

References
  1. []
  2. "Low Pressure Area forms near Tromelin Islands"
  3. https://www.aljazeera.com/news/2020/03/tropical-cyclone-herold-forms-coast-madagascar-200314085617745.html
  4. https://phys.org/news/2020-03-nasa-tropical-cyclone-herold-eye.html
  5. https://blogs.nasa.gov/hurricanes/tag/herold-2020/
  6. http://www.meteomadagascar.mg/cyclone
  7. https://www.gdacs.org/report.aspx?eventtype=TC&eventid=1000660
  8. https://reliefweb.int/report/madagascar/madagascarmauritius-cyclone-herold-flash-update-no-1-17-march-2020
  9. 17 March 2020. "Herold drenches Madagascar". Retrieved 24 March 2020.
  10. 16 March 2020. "Top News: Tropical Cyclone Herold drenches northeastern Madagascar" Retrieved 24 March 2020.
  11. 17 March 2020. "Sava and Analanjirofo - Over three thousand victims of Herold" Retrieved 25 March 2020.
  12. 16 March 2020. "Herold floods Maroantsetra" Retrieved 25 March 2020.
  13. 17 March 2020. "Cyclone Herold in Madagascar". Retrieved 27 March 2020.
  14. 17 March 2020."Precipitation: Rains expected in Antananarivo" Retrieved 27 March 2020.
  15. 22 March 2020. "Damage assessment: 4,771 victims after the passage of Herold" Retrieved 27 March 2020.
  16. 20 March 2020."Cyclone Herold: provisional assessment: Five dead and 1 missing" Retrieved 27 March 2020.
  17. 16 March 2020. "A dangerous Category 2 Tropical Cyclone #HEROLD will pass between Mauritius and Rodrigues Island on Tuesday - severe damaging threat for Rodrigues" Retrieved 23 April 2020.
  18. 20 March 2020. "NASA finds Herold a fading ex-tropical cyclone" Retrieved 23 April 2020.
  19. 16 March 2020. "NASA's Aqua satellite snaps new image of Cyclone Herold". Retrieved 23 April 2020.


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