Tropical Cyclone Freddy is the longest tropical cyclone on record at 36 days: WMO
The World Meteorological Organization (WMO) has declared Tropical Cyclone Freddy to be the longest-lasting tropical cyclone on record, at 36 days. Freddy crossed the Indian Ocean basin, starting off the coast of Northwest Australia and reached southern Africa, in February and March 2023. It caused major human and economic losses in the worst-affected countries.
- Freddy crossed the Indian Ocean basin in February-March 2023.
- Madagascar and southeastern Africa bore brunt of human and economic losses.
- Freddy was 36 days at tropical storm status or higher, beating record of John (1994)
- Freddy was 2nd longest in terms of distance travelled
- Monitoring of extremes increases understanding of weather and climate impacts.
A WMO international committee of experts working under the auspices of the Weather and Climate Extremes Archive conducted a detailed analysis and verification of the distance and duration. The evaluation committee recognized Tropical Cyclone (TC) Freddy’s duration of 36.0 days at tropical storm status or higher as the new world record for the longest tropical cyclone duration.
A reanalysis of the duration of the previous record holder TC John in the North Pacific Ocean in 1994 indicated that it existed at tropical storm status or higher for a combined duration of 714 hours, or 29.75 days.
In terms of distance, the WMO analysis indicated that TC Freddy travelled 12 785 km ± 10 km (7 945 miles, 6 905 nautical miles) at tropical storm status or above. This is a close second to TC John, which covered 13 159 km ± 10 km (8 177 miles, 7 105 nautical miles) at tropical storm status or above. To put that number in perspective, that distance is nearly 33% of the Earth’s circumference.
“Freddy was a remarkable tropical cyclone, not only for its longevity but also for its ability to survive multiple land interactions, which unfortunately had significant consequences for southeast African populations," says Chris Velden, committee member and tropical cyclone/satellite expert from the University of Wisconsin, USA.
“This investigation highlights the meticulous care that the WMO undertakes in certifying all weather observations. Such painstaking evaluation provides the critical confidence that our global records of all weather phenomena are properly measured,” said Randall Cerveny, Rapporteur of Climate and Weather Extremes for WMO.
WMO will update its Archive of Weather and Climate Extremes to reflect the new record. The archive includes the world’s highest and lowest temperatures, rainfall, heaviest hailstone, longest dry period, maximum gust of wind, longest lightning flash and weather-related mortalities. It is used by weather historians and, increasingly, by policy makers.
“The extremes presented for adjudication for the WMO Weather and Climate Extremes Archive are ‘snapshots’ of our current climate. It is possible, and indeed likely, that greater extremes will occur in the future. When such observations are made, new WMO evaluation committees will be formed to adjudicate these observations,” said Randall Cerveny.
The WMO evaluation committee consisted of experts from the Tropical Cyclone Warning Center Melbourne (Bureau of Meteorology, Australia), the Regional Specialized Meteorological Centre (RSMC) La Réunion (Météo-France, France) that forecasted TC Freddy, as well as scientists from Spain, Canada, Hong Kong China, and the United States
The findings were published in the online Bulletin of the American Meteorological Society.
Major impacts
Tropical Cyclone Freddy traversed the Indian Ocean Basin from off the northwest coast of Australia to multiple landfalls in Africa from 4 February to 14 March 2023.
Due to its prolonged passage near and over land, Freddy was particularly destructive, especially in Madagascar, Malawi and Mozambique.
More than 1 200 people were reported as dead or missing and more than 2 100 injured in Malawi. In Mozambique, more than 1.3 million people were affected, with more than 180 deaths. In Madagascar, nearly 200 000 people were affected by the first and second landfall.
According to the African Risk Capacity's Tropical Cyclone Explorer (TCE) model, the damage caused by FREDDY is estimated at 481 million US dollars.
Advance advisories of the storm by WMO’s Regional Specialized Meteorological Centre La Réunion (Meteo-France) and warnings by the national meteorological and hydrological services of affected countries allowed the disaster management and humanitarian communities to mobilize in advance, with evacuations and pre-positioning of food supplies. Without these warnings, the casualty toll would have been even higher.
“Tropical Cyclone Freddy was a text book example of the importance of the UN Early Warnings for All initiative to ensure that everyone is protected in the next five years. WMO is committed to working with our partners to achieve this and tackle extreme weather and climate change related risks - one of the biggest challenges of our times,” says WMO Tropical Cyclone Programme scientific officer Anne-Claire Fontan.
According to NASA, Freddy set the record for having the highest accumulated cyclone energy (ACE) of any southern hemisphere storm in history and was the equivalent of an average full North Atlantic hurricane season. ACE is an index used to measure the total amount of wind energy associated with a tropical cyclone over its lifetime.
The WMO Evaluation Committee did not consider ACE in pronouncing its record.
Evaluation
Since both tropical cyclones Freddy and John underwent episodic weakening below ‘tropical storm’ status during their lifetimes, the committee had to address whether the duration and distance values of a storm below tropical storm status should be considered in the calculations.
No such determination was conducted for TC John back in 1994. The committee decided to accept only observations of at least tropical storm status in WMO extremes decisions.
In this Extremes evaluation, the committee faced several decisions regarding not only the data of 2023’s TC Freddy, but also the accepted extremes recorded for 1994’s TC John. Unfortunately, information on the methods used to compute the precise numbers (duration and distance) listed for TC John has been lost.
Consequently, the team reconstructed the duration and distance numbers for TC John based on the best track data from the WMO RSMC Miami (National Hurricane Center (NHC), USA), the Joint Typhoon Warning Center (JTWC) and the WMO RSMC Tokyo (Japan Meteorological Agency (JMA)). Tropical cyclone track data are maintained by several WMO Regional Specialized Meteorological Centres, each responsible for a different region.
Notes to Editors
Members of the WMO extreme evaluation committee:
- Craig Earl-Spurr (Australia)
- Sébastien Langlade (La Réunion)
- Daniel Krahenbuhl (United States)
- Sim D. Aberson (United States)
- Manola Brunet (Spain)
- Johnny Chan (Hong Kong)
- Chris Fogarty (Canada)
- Christopher W. Landsea (United States)
- Blair Trewin (Australia)
- Christopher Velden (United States)
- Robert C. Balling (United States)
- Randall Cerveny (United States)
Details on the working of the WMO Extremes Archive and paste evaluations are presented in a book by Randy Cerveny entitled “Judging Extreme Weather : Climate Science in Action » published by Routledge Publishing.
The World Meteorological Organization (WMO) is a specialized agency of the United Nations responsible for promoting international cooperation in atmospheric science and meteorology.
WMO monitors weather, climate, and water resources and provides support to its Members in forecasting and disaster mitigation. The organization is committed to advancing scientific knowledge and improving public safety and well-being through its work.
For further information, please contact:
- Clare Nullis WMO media officer cnullis@wmo.int +41 79 709 13 97
- WMO Strategic Communication Office Media Contact media@wmo.int