Tropical cyclone · Southern Indian Ocean and southern Africa
Freddy: thirty-six days across an ocean
Freddy formed off north-western Australia in early February 2023 and did not die until mid-March, over Malawi. In between it crossed the Indian Ocean from east to west, reached its peak near Mauritius' longitude, made landfall in Madagascar and Mozambique, looped back over the Mozambique Channel, gathered strength again and struck Mozambique a second time. The World Meteorological Organization later confirmed it as the longest-lasting tropical cyclone ever recorded: 36 days, 12,785 km. [N1]
4 February – 14 March 2023 · Madagascar, Mozambique, Malawi · ERA5
140kt
Peak wind, 19 February
About 260 km h⁻¹ sustained, with 923 hPa at the centre, over the open ocean.S1
What happened
Freddy was named on 6 February south of the Indonesian islands and moved west across the southern Indian Ocean for more than two weeks, strengthening and weakening several times over the open ocean. Its accumulated energy (ACE) was the highest of any storm on record in the Southern Hemisphere: about as much as an average whole North Atlantic hurricane season.N1N2
It crossed Madagascar, then Mozambique, and seemed to be dying inland. Instead it drifted back out over the warm Mozambique Channel, grew again, looped, and came ashore a second time near Quelimane on 11 March. From there it moved slowly inland over southern Malawi, where days of rain fell on steep, crowded hillsides.N3
4–6 Feb
Forms off north-western Australia; named Freddy.S1
19 Feb
Peak intensity in the central Indian Ocean: 140 kt, 923 hPa.S1
21 Feb
Landfall on the east coast of Madagascar.
24 Feb
Landfall in southern Mozambique; the storm weakens inland, then drifts back over the sea.
11 Mar
Second landfall in Mozambique, near Quelimane, stronger than the first.
12–14 Mar
Over southern Malawi: floods and mudslides in Blantyre. The storm dissipates.N3
Freddy on the Lab's maps
ERA5 follows the whole journey. On 19 February the storm is a small, isolated ring of wind in the middle of the ocean; two days later it reaches Madagascar; on 11 March it sits on the Mozambican coast after its loop. In each map the core is broader and weaker than the real storm, as in every global reanalysis, but the track and timing are right.
The rain over Malawi
By the time Freddy reached Malawi its wind had faded; its rain had not. The slow-moving remnant drew moist air off the Mozambique Channel and the warm lakes for three days. On ERA5's map of 13 March, the heaviest rain, over 80 mm in a day, covers southern Malawi and the Shire valley around Blantyre.
357mm
ERA5's rain at Blantyre in three days, 12–14 March, almost three times its normal rain for the whole of March (129 mm). A reanalysis grid smooths the heaviest showers, so the gauges on the hills will have caught more.
| Day | Rain |
|---|---|
| Mar 12 | 87.6 |
| Mar 13 | 159.2 |
| Mar 14 | 110.0 |
| Three days | 356.8 |
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References
News
- N1World Meteorological Organization. Tropical Cyclone Freddy is longest tropical cyclone on record at 36 days: WMO. 1 July 2024.The record: 36 days, 12,785 km, the energy, and the toll in each country.
- N2NOAA Climate.gov. From Australia to Africa in 36 days: Freddy was the longest-lasting tropical cyclone in history. 9 July 2024.The storm's journey and why it lasted so long.
- N3UN OCHA. Malawi: Tropical Cyclone Freddy, Flash Update No. 11. 31 March 2023.Deaths, missing and mudslides in Malawi at the end of March 2023.
Studies and guidelines
- S1Knapp, K. R., et al. (2010). The International Best Track Archive for Climate Stewardship (IBTrACS): unifying tropical cyclone data. Bulletin of the American Meteorological Society, 91, 363–376.The best-track data set: Freddy's positions and winds, also drawn on the Events map.