Hurricane Harvey Rainfall Effects on Texas

Garrett Johnston

Hurricane Harvey made landfall as a Category 4 storm the night of Aug. 25 between Port Aransas and Port O’Connor, Texas. As it moved across Texas, the storm proceeded to dump catastrophic amounts of rain. Please see below our exhibits, which illustrate the magnitude of rainfall that fell over the most intense 24 hours of the storm and a 3-day period (Aug. 26 through Aug. 28).

The Probable Maximum Precipitation (PMP) is the theoretically greatest depth of precipitation for a given duration that is physically possible over a given storm area at a particular geographic location. For the 24-hour duration, some areas in Harris and Liberty Counties experienced more than 60 percent PMP. For the 72-hour duration, most of Harris, Liberty and Fort Bend Counties experienced more than 60 percent PMP, with some areas in Liberty County reaching upward of 90 percent PMP.