NOAA GOES-East ABI Infrared image of the July 2025 Texas flooding event.
In the early hours of July 4, 2025 a devastating flash flood occurred in the Central Texas Hill Country. The Guadalupe River in Kerr County rose over twenty feet in just a few hours, and more than a hundred people lost their lives and thousands of residents' homes were destroyed.
Kerr County highlighted in tan and Guadalupe River in blue.
Most flash floods are caused by slow-moving thunderstorms which move over the same area one right after the other. Flash floods develop over a short time period, making them life threatening. Areas most susceptible to flash flooding are mountainous streams, urban areas, low-lying areas, storm drains, culverts and rivers.
NOAA’s National Geodetic Survey on damaged properties line the Guadalupe River in Kerr County, Texas following the devastating flooding that occurred on July 4, 2025.
NOAA’s National Weather Service (NWS) plays a vital role in issuing flash flood watches and warnings. Other NOAA offices such as the Center for Satellite Applications and Research (STAR) provide data and information to NWS that allows them to detect potential flooding and issue timely and accurate warnings. STAR’s Microwave Integrated Retrieval System (MiRS) product is derived from six satellites, including NOAA-20 and 21. MiRS provides timely and effective information on water vapor and precipitation to support NWS flood alert operations.
One of the MiRS products, Water Vapor Profile, is the only satellite input to the Advected Layer Precipitable Water (ALPW), a 4-D imagery structure of water vapor in the atmosphere. ALPW was developed by the Cooperative Institute for Research in the Atmosphere (CIRA), a partner of NOAA.
Prior to the devastating flood in Kerr County, NWS’s Weather Prediction Center (WPC) issued a Mesoscale Precipitation Discussion (MPD), a statement that highlights the potential for significant flooding in an area that often precedes a flood watch or warning. The MPD mentioned that the ALPW imagery revealed an extremely moist environment with water vapor contributions from both the Gulf of America and the Tropical Eastern Pacific region. The detection of this combination of moisture sources tipped off WPC forecasters to the threat of extreme precipitation in the area, resulting in the MPD that alerted local NWS forecasters of an escalating flash flood risk in central Texas, including Kerr County.
The figure below shows the four layer precipitable water layers in millimeters of atmospheric moisture from the ALPW product, where the water vapor contributions are from the Gulf of America and the Tropical Eastern Pacific on July 4, 2025.
ALPW product showing water vapor contributions from the Gulf of America and the Tropical Eastern Pacific. July 4, 2025.
Additionally, MiRS measures rain rate and serves as a data input for NWS’s Climate Prediction Center (CPC) CMORPH, a dataset collection of global precipitation to support meteorology and hydrology studies. CMORPH2 showed a centralized intense precipitation in the same region in Texas Hill Country.
Captured precipitation locations and intensity in central Texas during the recent devastating flooding event.
Flooding is a hazard that endangers lives as one of the leading weather-related killers. Having tools and products like MiRS supports NWS in issuing life-saving alerts.