World Rainfall Records for 24- and 48-Hour Periods
The U.N. WMO (World Meteorological Organization) recently announced that a ‘new’ world record for a 48-hour (or two day) period has been confirmed following an investigation by a group of climatologists from around the world. The figure is said to be an amazing 2,493 mm (98.15”) at Cherrapunji, India that fell on June 15-16, 1995. However, this may not be what was truly the greatest 48-hour precipitation record.48-hour World Precipitation Records
Previous to the now officially recognized Cherrapunji 48-hour record mentioned above, the previous record was thought to be 2,467 mm (97.13”) set on March 15-17, 1952 at Cilaos, Reunion Island, a French territory in the Indian Ocean. However, the WMO committee does not appear to have been aware of (or dismissed) an even greater 48-hour total that also occurred on Reunion Island on February 27-March 1, 1993 when a site identified as Baril 1600 (the 1600 refers to the site’s elevation of 1,600 m/6,300’) measured 3,000.5 mm (118.13”) during an intense generalized rainfall event associated with Tropical Depression Hutelle that affected the island from February 27 to March 5 that year. This rainfall event was the subject of a scholarly article in the December 1997 issue of Monthly Weather Review
, Vol. 125, pp. 3341-3346. The article states that the rain gauge at Baril 1600 was part of a 5-year investigation of water resources on the Piton de la Fournaise massif on Reunion Island undertaken by the University of Reunion Island. This may be the reason that the WMO has not accepted the Baril 1600 reading, since the gauge was not part of the official Meteo France (French Meteorological Organization) rain gauge network on the island. Nevertheless, the equipment used in the research project was of exacting standards and the measurement at Baril 1600 was in line with other measurements made in the region during the event.Geographic location of rain gauges on the Piton de la Fournaise massif used in the study. The Baril transect is where the heaviest rainfall apparently occurs on a regular basis on the island. The back circles indicate the location of official Meteo France rain gauges and the numbered squares the gauges used in the research project.
Map from ‘Monthly Weather Review’ article by Alain Barcelo et al.Above is a table of the 7 a.m. to 7 a.m. local time 24-hour precipitation totals (in millimeters) for the sites listed on the map above during the period of February 27-March 4, 1993. The 3000.5 mm 48-hour total for the Baril1600 location occurred between 8.33 p.m. on February 27 and 8:33 p.m. on March 1st.
Table from ‘Monthly Weather Review’ article.A table comparing the Baril 1600 rainfall event of February 27-March 5, 1993 to the Reunion Island and world all-time precipitation records for various periods of time. World records are in bold.
Table from ‘Monthly Weather Review’ article.24-hour World Precipitation Records
It is generally acknowledged (and officially accepted by the WMO) that the greatest 24-hour rainfall record also occurred on Reunion Island at the site of Foc-Foc on January 7-8, 1966 when 1,825 mm (71.85”) on rainfall was measured during Tropical Storm Denise. There is also an unofficial 24-hour total of 1,870 mm (73.62”) at Cilaos on March 15-16, 1952 that is cited by J.L.H. Paulhus in a Monthly Weather Review
article published in 1965 (Vol. 93 No. 5, pp. 331-335). This record has been discounted by Meteo France.
Outside of Reunion Island the world record for a 24-hour rainfall is the 1,637 mm (64.45”) that fell on Isla Mujeres (an island of the coast of the Yucatan Peninsula), Mexico on October 21-22, 2005 during the passage of Hurricane Wilma, the most intense tropical storm ever observed in the Western Hemisphere. There is a mention of a 1,672 mm (65.83”) 24-hour precipitation figure at Xinliao, Taiwan on October 17-18, 1967 in some Chinese publications, but this figure is unofficial and dubious.
A very close second to the Isla Mujeres figure is a little reported event that took place in central Vietnam on November 2-3, 1999 when 1,630 mm (64.17”) of rainfall fell on Truoi. Nearby, the city of Hue was inundated with 1,422 mm (55.98”) in the same 24-hour period resulting in floods that killed at least 622 and destroyed 42,000 homes. The streets of downtown Hue were swamped under 3 meters (10’) of floodwater.Map of the region in central Vietnam affected by the tremendous rainfall of November 2-3, 1999.
From ‘Monthly Weather Review’ Vol. 136, No. 9, September 2008 article by S. Yokoi about heavy rainfall events in central Vietnam.The flood in Hue in early November 1999 damaged many of the city’s famous historical sites.
Photograph from a Vietnamese climate science journal.Table of 24 and 48-hour precipitation totals at Hue and Truoi on November 2-3, 1999. Note the near world-record (excluding Reunion Island) amounts not just for 24 hours but also 48 hours for which Truoi picked up 2,200 mm (86.61”).
Table from Vietnamese climate journal.
For the U.S., the record 24-hour rainfall was the 43.00” (1,092 mm) reported from Alvin, Texas on July 25-26, 1979 during Tropical Storm Claudette. More about this storm and other great 24-hour rainfalls from around the world can be found in this blog I posted last October.
However, since I wrote the October blog new information, like the rainstorm in Vietnam, has dated some of the material and the list of locations with 40”+ rain events is questionable. For instance, the Australian 24-hour record should be 960 mm (37.80”) not the 1142 mm (44.92”) listed, which was an estimated amount. Also, the Amini Devi, India figure is not reliable, a result of a typographical error in the Indian records. I will re-publish a more accurate accounting of this in a future blog.KUDOS:
Thanks to Maximiliano Hererra for bringing the Vietnamese rain event to my attention.
Christopher C. Burt