National 24-hour Precipitation Records
Earlier this week, on July 28th, both Holland and Germany saw some incredible rainfalls that approached their respective all-time national records for greatest 24-hour precipitation totals. Here are some details on these events as well as a ‘potted’ list of some other national records of such.Munster, Germany Deluge of July 28th
On the afternoon of July 28th heavy thunderstorms developed over portions of western Germany and remained stationary for several hours depositing prodigious amounts of rainfall in and around the city of Munster (among other sites). A rain gauge at Munster’s main sewage works measured 292.5 mm (11.52”) of rainfall in a 7-hour period between 17:00-00:00 UTC. Of this, an amazing 163.5 mm (6.44”) fell in a single hour ending at 20:00 UTC and 261.5 mm (10.30”) in just 3 hours (see table below). Hourly precipitation totals at the Munster Sewage Works Station on July 28th. The daily total of 292.5 mm (11.52”) was likely the 2nd greatest such on record for Germany.
Thanks to Michael Theusner for link to this data.
According to Michael Theusner of Klimahaus in Bremerhaven, Germany, the 292.5 mm figure was likely the 2nd greatest 24-hour precipitation to be officially observed in modern German climate records (following the national record of 353 mm/13.90” at Zinnwald-Georgenfeld on August 12-13, 2002 during the great Elbe Flood that summer). The one-hour total of 163.5 mm might also have been the 2nd greatest for such a period of time, being short of the 200 mm (7.87”) that deluged the town of Miltzow in one hour on September 15, 1968. The three-hour total is almost certainly a new German record for that time period, although records for three-hour rainfalls are not on the books.Table of official German national precipitation records for various periods of time. Those highlighted were related to the disastrous Elbe River floods in August of 2002.
Table from monograph about Elbe River floods written by Bruno Rudolf and Jorg Rapp for the DWD-Offenbach, 2003. Netherland’s Rainfall on July 28th
Another cluster of thunderstorms, similar to those that brought the deluge to Munster on July 28th, also affected portions of Holland where 24-hour precipitation totals topped out at 160 mm (6.30”) in Maarssen/Utrecht and 132 mm (5.20”) at Deelen. Radar estimated totals in the Maarssen/Utrecht area indicated rainfall accumulations as high as 210 mm (8.27”). Being estimated, these are not considered as official and thus fall short of the ‘official Dutch national 24-hour precipitation record’ of 208 mm (8.19”) set at Voorthuizen on August 2-3, 1948. At Deelen, 76 mm (2.99”) of the rainfall occurred in a single-hour period, which is just short of the national record for such of 79 mm (3.11”) set in an hour at Herwijnen on June 28, 2011.Measured rainfall totals for the 48-hour period of July 27-29 in the Netherlands. Virtually all of these amounts fell on July 28th.
Map from Koninklijk Netherlands Meteorological Institute.Some Other Possible National 24-hour Precipitation Records
Below is a chart of some other possible national 24-hour precipitation records from a selection of various countries around the world. This is a ‘potted’ list at best, and although some of the figures (especially some of those for Europe, North America, Australia, New Zealand, and certain countries in Asia and South America) are considered ‘official’ by the nation’s respective meteorological agencies most of the figures are simply what I have been able to discover researching published works such as Elsevier’s 15-volume ‘World Survey of Climatology’ series and the U.K. Met Office’s ‘Tables for Temperature, Relative Humidity and Precipitation for the World’ (a six-volume series) as well as many other scientific books and journals related to national climatologies. However, that being said, many of the above mentioned works date to the 1960s and 1970s and so do not reflect more recent data.
Unfortunately, I am only rendering the precipitation amounts in inches rather than including metric figures since, in many cases, the figures have been translated back and forth already between the two measuring systems and inaccuracies increase with each new translation. At some future date, when I have more time, I will go back and source each of the figures and determine whether the original data was provided in English units or metric units.
I simply include this list as something of interest, not to be considered an actual reliable list of official records. Hopefully, some readers will be able to correct, update, or add some more data to the list. A FEW NOTES:
The Chinese figure is of very dubious accuracy. The Indian figure is derived from a two-day measurement of 98.15” and so it is likely that the wettest single 24-hour period during this event was greater than half the total. Much higher figures for Japan and Taiwan have appeared in scientific literature but are not included since those figures have not been officially recognized by their respective meteorological agencies. The U.S. record is derived from a bucket-survey and appears to have recently been modified from 43” to 42”. Although the NCDC has rejected other ‘bucket survey’ figures in the past, for some reason they seem to be willing to consider the Alvin figure reliable and “official”.KUDOS:
Thanks to Michael Theusner of Klimahaus, Bremerhaven for German data and blog reader RRKampen for Netherlands information.
Christopher C. Burt