“Worse than a Typhoon”.
On a warmer planet, we no longer need a major cyclone to cause major cyclone damage.
Total rainfall measured at 800 mm (31.5 inches).
The Hong Kong Observatory said that 6.22 inches of rain had fallen in the hour from 11 p.m. Thursday (11 a.m. ET Thursday) to midnight, the highest recording since records began in 1884.
It also issued its highest “black” warning for the first time in two years, lasting for more than 15 hours from 11:05 p.m (11:05 a.m. ET) — the longest “black rainstorm” in the city’s history.
The Hong Kong Observatory, the government department responsible for monitoring and forecasting weather, said a trough of low pressure associated with remnants of Typhoon Haikui brought heavy rain and thunderstorms to the Pearl River Estuary. More than 600 mm of rainfall were recorded at the Observatory in the past 24 hours to 08 September Rainfall totals exceeded 800 mm over the Eastern District and Southern District of Hong Kong Island, the Observatory said. The monthly mean rainfall for September in Hong Kong is 321.4 mm.
As with 2017 Hurricane Harvey, the proposed Galveston/Houston Ike Dike would be no use in these ever more common mega rain events, and would definitely need to take care not to make it harder for water coming off of land to leave the Houston Channel and Galveston Bay.