Hurricane Harvey left streets and houses flooded after making landfall. The 347th Rescue Group from Moody Air Force Base, Ga. responded with its rescue aircraft and personnel in support of FEMA after Hurricane Harvey brought flooding and destruction to parts of Texas. (U.S. Air Force photo by Tech. Sgt. Zachary Wolf)
Flooding is among the most frequent and costly natural disasters in the United States, affecting thousands of communities annually. As climate change increases flood risks, accurate forecasting and resilience tools are more essential than ever.
NOAA’s National Environmental Satellite, Data, and Information Service (NESDIS) plays a crucial role in preparing communities for floods. NESDIS, alongside international partners, collects vital data that inform flood forecasting. By transforming this data into actionable insights, NOAA warns communities of imminent threats and helps reduce long-term risks.
Understanding Flooding Beyond Rainfall
Flooding is complex and not solely caused by heavy rainfall. Rapid snowmelt can send excess water into rivers and streams, leading to floods. Flooding can also occur downstream from where precipitation falls, as water travels through river systems and overwhelms areas that didn't receive rain. This complexity makes flood forecasting more challenging than simply predicting rainfall locations.
NOAA Satellites Collect Crucial Data
NOAA operates satellites like the Geostationary Operational Environmental Satellites (GOES) and the Joint Polar Satellite System (JPSS), key for monitoring Earth's weather and climate. These satellites use specialized sensors to observe atmospheric conditions, such as clouds, moisture levels, and precipitation.
Visible and Infrared (VIS/IR) Sensors: Under clear skies, visible light sensors capture images of affected regions, while infrared sensors detect temperature differences to identify flooded areas. Instruments like the GOES Advanced Baseline Imager (ABI) and the JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) provide detailed imagery that supports real-time flood assessment.
Floodwater depth map of Florida’s coast near Cape Coral, captured on October 10, 2024, following Hurricane Milton. The data was collected by the Visible Infrared Imaging Radiometer Suite (VIIRS)
Synthetic Aperture Radar (SAR): In collaboration with partner nations, NOAA uses SAR data, which can penetrate clouds and detect surface conditions, effectively identifying flooded areas even in challenging weather.
Transforming Data into Actionable Insights
Collected satellite data is transmitted to ground stations for processing and analysis. By combining this data with local weather radar and ground sensors — a process known as data fusion — NOAA creates a comprehensive picture of current and potential conditions. Specialized algorithms are used to detect flooding with high accuracy.
Investments from the Bipartisan Infrastructure Law have enhanced NOAA's capabilities, leading to higher-resolution flood mapping, reduced uncertainties, better flood depth estimations, increased satellite coverage during flood events, and improved integration of data sources. Additionally, Global partnerships allow NESDIS to gather environmental data worldwide, further enhancing flood forecasts and risk assessments.
Processed data is fed into advanced computer models that simulate storm development, rainfall patterns, and river responses. These models are essential for producing accurate flood forecasts. NOAA issues forecasts and warnings to emergency managers, authorities, and the public; ideally providing enough lead time for communities to prepare.
Building Long-Term Resilience
Long-term satellite data supports broader resilience efforts. By analyzing historical and current data, NOAA improves insights into flood frequency and severity. This information guides communities in making strategic infrastructure investments, such as enhancing drainage systems and constructing levees and floodwalls.
Improving flood resilience mitigates the long-term economic and social impacts of flooding, protecting property, lives, and local economies from disruptions.