Floodwater derived from Visible Infrared Imaging Radiometer Suite (VIIRS) instrument for the Washington Atmospheric River December 2025

Date of Image(s): May 4, 2024-May 8, 2024 Date of Next Image: Typically, there are two daytime images expected each day around 1:00pm EST. Summary: Floodwater derived from Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard NASA and NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. VIIRS floodwater product was produced by NASA SatCORPS Ground Station Observation Network (GSON) low latency system.. The image shows where floodwater was detected from the VIIRS observation. Suggested Usage: The floodwater fraction percentage (1-100%) that contains water Satellite/Sensor/Resolution: 375m spatial resolution VIIRS instrument onboard SNPP Satellite Generated using CSPP v4.1 Credits: Image Credit: NASA Langley SatCORPS Louis Nguyen of NASA Langley SatCORPS: https://satcorps.larc.nasa.gov/new/ NOAA Joint Polar Satellite System (JPSS) VIIRS Data: https://registry.opendata.aws/noaa-jpss/ Additional information on VIIRS Flooding products: https://disasters-geoplatform.hub.arcgis.com/pages/viirs-floodwater-fraction-map/

Date of Image(s): September 12, 2018-September 19, 2018 Date of Next Image: Typically, there are two daytime images expected each day around 1:00pm EST. Summary: Floodwater derived from Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard NASA and NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. VIIRS floodwater product was produced by NASA SatCORPS Ground Station Observation Network (GSON) low latency system.. The image shows where floodwater was detected from the VIIRS observation. Suggested Usage: The floodwater fraction percentage (1-100%) that contains water Satellite/Sensor/Resolution: 375m spatial resolution VIIRS instrument onboard SNPP Satellite Generated using CSPP v4.1 Credits: Image Credit: NASA Langley SatCORPS Louis Nguyen of NASA Langley SatCORPS: https://satcorps.larc.nasa.gov/new/ NOAA Joint Polar Satellite System (JPSS) VIIRS Data: https://registry.opendata.aws/noaa-jpss/ Additional information on VIIRS Flooding products: https://disasters-geoplatform.hub.arcgis.com/pages/viirs-floodwater-fraction-map/

Date of Image(s): May 4, 2024-May 8, 2024 Date of Next Image: Typically, there are two daytime images expected each day around 1:00pm EST. Summary: Floodwater derived from Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard NASA and NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. VIIRS floodwater product was produced by NASA SatCORPS Ground Station Observation Network (GSON) low latency system.. The image shows where floodwater was detected from the VIIRS observation. Suggested Usage: The floodwater fraction percentage (1-100%) that contains water Satellite/Sensor/Resolution: 375m spatial resolution VIIRS instrument onboard SNPP Satellite Generated using CSPP v4.1 Credits: Image Credit: NASA Langley SatCORPS Louis Nguyen of NASA Langley SatCORPS: https://satcorps.larc.nasa.gov/new/ NOAA Joint Polar Satellite System (JPSS) VIIRS Data: https://registry.opendata.aws/noaa-jpss/ Additional information on VIIRS Flooding products: https://disasters-geoplatform.hub.arcgis.com/pages/viirs-floodwater-fraction-map/ Esri REST Endpoint: See URL to the right. WMS Endpoint: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_EX2602_202405_FLOOD_BRAZIL/ex2602_viirs_FloodwaterFraction/MapServer/WMSServer

Date of Image(s): May 7, 2022; May 5, 2022 Date of Next Image: Typically, there are two daytime images expected each day around 1:00pm EST. Summary: Floodwater derived from Visible Infrared Imaging Radiometer Suite (VIIRS) instrument onboard NASA and NOAA Suomi National Polar-orbiting Partnership (Suomi NPP) satellite. VIIRS floodwater product was produced by NASA SatCORPS Ground Station Observation Network (GSON) low latency system.. The image shows where floodwater was detected from the VIIRS observation. Suggested Usage: The floodwater fraction percentage (1-100%) that contains water Satellite/Sensor/Resolution: 375m spatial resolution VIIRS instrument onboard SNPP Satellite Generated using CSPP v4.1 Credits: Image Credit: NASA Langley SatCORPS Louis Nguyen of NASA Langley SatCORPS: https://satcorps.larc.nasa.gov/new/ NOAA Joint Polar Satellite System (JPSS) VIIRS Data: https://registry.opendata.aws/noaa-jpss/ Additional information on VIIRS Flooding products: https://disasters-geoplatform.hub.arcgis.com/pages/viirs-floodwater-fraction-map/ REST Endpoint: See URL to the right. WMS Endpoint: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_EX2603_202205_FLOOD_MN/ex2603_viirs_FloodwaterFraction/MapServer/WMSServer

Dates of Images: Post-Event: Dec 10, 2025 Pre-Event: Dec 7, 2025 Date of Next Image: Dec 11, 2025 Summary: We developed a rapid-response workflow to map flooded areas during this emergency event using multi-temporal Sentinel-1 SAR data. Sentinel-1’s SAR backscatter characteristics are particularly effective for detecting surface water: water surfaces typically exhibit low backscatter, whereas non-water areas show higher backscatter. Leveraging this physical property, we distinguished between water and non-water surfaces from both pre- and post-flood observations. To highlight flood-induced surface changes, we computed the differenced co-polarized VV backscatter (dVV = VV_post – VV_pre). This change detection technique enhances the visibility of newly inundated areas. We then applied a simple threshold to the dVV image to separate flooded from non-flooded areas. Suggested Use: The final output is a binary raster product, where pixels with a value of 1 represent flooded areas (dark blue color). A permanent water body layer and a binary layer incorporating land cover are also included. The land cover information is derived from the 10m ESA world cover product: https://esa-worldcover.org/en Satellite/Sensor: Sentinel-1 /Synthetic Aperture Radar (SAR) Resolution: 10 meters Credits: Dr. Khuong H. Tran (Khuong.tran@nasa.gov) Esri REST Endpoint: See URL section on right side of page WMS Endpoint: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_202512_FLOOD_WA/2512_sentinel1_FloodDetection/MapServer/WMSServer

Dates of Images: Pre-Event: October 13, 2025 Post-Event: December 17, 2025 Date of Next Image: Unknown Summary: The True Color RGB composite provides a product of how the surface would look to the naked eye from space. The RGB is created using the red, green, and blue channels of the respective instrument. The Color Infrared composite is created using the near-infrared, red, and green channels. The near-infrared gives the ability to see through thin clouds. Healthy vegetation is shown as red, water is in blue. Suggested Use: The True Color RGB provides a product of how the surface would look to the naked eye from space. The True Color RGB is produced using the 3 visible wavelength bands (red, green, and blue) from the respective sensor. Some minor atmospheric corrections have occurred. A Color Infrared composite depicts healthy vegetation as red, water as blue. Some minor atmospheric corrections have occurred. Satellite/Sensor: MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/2B satellites Resolution: 10 meters Credits: NASA/MSFC, USGS, ESA Copernicus Esri REST Endpoint: See URL section on right side of page WMS Endpoint: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_202512_FLOOD_WA/2512_sentinel2/ImageServer/WMSServer