Remote Sensing of Record-Setting Floods of Spring 2019 in the Central United States

Abstract:

Beginning in the early spring months of 2019, the combination of extensive and deep snow cover, rapid warming, heavy rainfall, and rainfall-induced snowmelt contributed to the rapid development of extensive, damaging, and record-setting flooding in the Platte River and Missouri River basins of the Central United States. In mid-March, these events contributed to extensive and long-lasting flooding of the Missouri River impacting southeastern Nebraska, northwestern Iowa, central Missouri, and impacts further downstream within the basin. To support U.S. state and federal partners during their immediate response and recovery efforts, water detections were performed by using threshold-based approaches on European Space Agency Sentinel-1 synthetic aperture radar (SAR), Sentinel-2 optical, USGS/NASA Landsat, and other imagery contributed through the USGS Hazards Data Distribution System. Many of these approaches during the event focused on near real-time response, application of relatively quick and simple thresholds on individual scenes or derived products and helped to inform users about water extent and impacts on local infrastructure. Post-event, further efforts were made to explore more rigorous methods for mapping water extent through automated estimation of ideal backscatter thresholds to improve outputs from SAR mapping. Further, collaborations with partners internal to NASA and at the University of Alabama sought to develop additional value-added information to estimate floodwater depth as a key metric for improving damage assessments in line with thresholds used by the Federal Emergency Management Agency and other U.S. partners. This presentation will highlight methods and results from flood mapping efforts during the Spring 2019 floods and continued long-term flooding that followed in the remainder of the year, discuss strengths and weaknesses of various approaches, highlight opportunities for collaborative flood mapping with geostationary and other low-Earth orbit imagery facilitated by NOAA, and examine how these tools can be more effective in supporting near real-time mapping for future flood scenarios.