The torrential rains that flooded Kauai in April set a national record for the most rainfall in a 24-hour period, weather officials confirmed today.
The National Weather Service’s National Climate Extremes Committee issued a memorandum this morning verifying the new record, noting that heavy rains across the eastern and northern Kauai resulted in multiple reports of flooding on April 14 and 15.
A total of 49.7 inches fell at Waipa Garden in the 24-hour period ending 12:45 p.m. on April 15, breaking the previous U.S. record of 43 inches on July 25-26, 1979, near Alvin, Texas, from Tropical Storm Claudette, according to the committee.
“After considering the observation and the various surrounding factors, the NCEC determined the Waipa Garden observation to be valid, and it now stands as the 24-hour record precipitation for the United States,” said the committee in the memorandum.
The committee said that most of the record-setting rain came in three bursts. On April 14, nearly 20 inches fell from afternoon to evening, followed by about 18 inches in the early morning of April 15, and another 8 inches in the late morning and early afternoon.
The torrential rains resulted in catastrophic flooding in mid-April, closing schools and causing millions of dollars of damage to roads, homes and infrastructure on Kauai.
The Waipa Garden rain gauge, operated by the nonprofit Waipa Foundation, is just west of Hanalei in a meadow about 300 yards inland from Hanalei Bay, the committee said. While it is not part of the NWS official observing network, it is known to the local forecast office as an occasional provider of data and is considered reliable and accurate, officials said.
In late April, weather service officials said the Waipa Garden measurement was a possible national record but that the committee had to investigate and verify the information before being entered into the record books.
Kauai’s 24-hour rainfall is now officially posted in the committee’s list of records, including minimum and maximum temperatures, largest hail and longest dry period. The record maximum annual rainfall of 704.83 inches in 1982 is held by another Hawaii location: Pu‘u Kukui in West Maui.