OPERA Surface Disturbance Map from Harmonized Landsat Sentinel-2 for Hurricane Helene

Date of Images: 10/11/2024, 10/12/2024 Summary: The Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at NASA's Jet Propulsion Laboratory and California Institute of Technology derived the disturbance maps using the OPERA Disturbance Alert from Harmonized Landsat Sentinel-2 (DIST-ALERT-HLS) products. The results posted here are preliminary and unvalidated results, primarily intended to aid the field response and people who want to have a rough first look at the surface disturbance extent. The ARIA-share website has always focused on posting preliminary results as fast as possible for disaster response. OPERA DIST-ALERT-HLS The Disturbance product (DIST) maps per pixel vegetation disturbance (specifically, vegetation cover loss) from the Harmonized Landsat Sentinel-2 (HLS) scenes. We provide the vegetation disturbance status (VEG-DIST-STATUS) and the maximum vegetation anomaly value (VEG-ANOM-MAX) layers. Images are provided from October 2, 2024. Each image consists of multiple MGRS tiles that were merged together for a composite image saved as a GeoTIFF file. VEG-ANOM-MAX Difference between historical and current year observed vegetation cover at the date of maximum decrease (vegetation loss of 0-100%). This layer can be used to threshold vegetation disturbance per a given sensitivity (e.g. disturbance of >20% vegetation cover loss). The sum of the historical percent vegetation and the anomaly value will be the vegetation cover estimate for the current year. GEN-ANOM-MAX Maximum spectral distance between a current year HLS scene reflectance and the composite reflectance of previous calendar years. Generic disturbance, as determined from the variations of the reflectance through the HLS scenes, is intended to delineate generic changes outside of the vegetation cover loss theme. The DIST-ALERT HLS products have these flags: For VEG-ANOM-MAX layers, 255 represents No Data and is based on the Fmask layer of the source HLS granule. For the GEN-ANOM-MAX layer, -1 represents "No Data" and is based on the Fmask layer of the source HLS granule. Suggested Use: VEG-ANOM-MAX 0 (White) - 100 (Red): Maximum loss of percent vegetation 255: No data GEN-ANOM-MAX 0 (White) - Variable (Blue): Maximum spectral distance compared to composite reflectance of previous calendar years -1: No Data Satellite/Sensor: MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/B satellites and Operational Land Imager 2 (OLI-2) on NASA's Landsat 9 satellite. Resolution: 30 meters Credits: NASA JPL-Caltech ARIA/OPERA Team The product contains modified Copernicus Sentinel data (2024) and is produced as part of the OPERA project, which is funded by NASA to address remote sensing needs identified by the Satellite Needs Working Group. Managed by NASA's Jet Propulsion Laboratory, OPERA funds and manages the DIST-ALERT-HLS product developed and produced by the Global Land Analysis and Discovery (GLAD) laboratory at the University of Maryland. Additional Information: The OPERA DIST-HLS products have been in production since January 2022, are freely distributed to the public via NASA's Land Processes Distributed Active Archive Center (LP DAAC), and can be downloaded through NASA's Earthdata search. For more information about the Surface Disturbance product suite, please refer to the DIST Product page: https://www.jpl.nasa.gov/go/opera/products/dist-product-suite/ For more information about the Caltech-JPL ARIA project, visit https://aria.jpl.nasa.gov For more information about the JPL OPERA project, visit https://www.jpl.nasa.gov/go/opera/ Data Download: https://aria-share.jpl.nasa.gov/20241010-Hurricane_Milton/DIST/ Service URL: https://gis.earthdata.nasa.gov/portal/home/item.html?id=dfe2b9e3f03b468a89286e06eb60e4be WMS: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_202410_HURRICANE_MILTON/2428_opera_dist_hls/ImageServer/WMSServer

Dates of Images: Post-Event: 10/1/2024 (Landsat 8), 10/2/2024 (Landsat 9), 10/9/2024 (Landsat 9) Pre-Event: 8/30/2024 (Landsat 8) Date of Next Image: Unknown Summary: Natural Color: The Natural Color RGB provides a false composite look at the surface. This RGB uses a shortwave, the near-infrared, and red channels from the instrument. Color Infrared: The Color Infrared composite is created using the near-infrared, red, and green channels, allowing for the ability to see areas impacted from the fires. The near-infrared gives the ability to see through thin clouds. Healthy vegetation is shown as red, water is in blue. True Color: 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. Suggested Use: Natural Color: areas of water will appear blue, healthy green vegetation will appear as a bright green, urban areas in various shades of magenta. Color Infrared: depicts healthy vegetation as red, water as blue. Some minor atmospheric corrections have occurred. True Color: 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. Satellite/Sensor: Landsat 8 and Landsat 9 Operational Land Imagers (OLI) Resolution: 30 meters Credits: NASA/MSFC, USGS Esri REST Endpoint: See URL section on right side of page WMS Endpoint: https://gis.earthdata.nasa.gov/portal/services/DISASTERS_202409_HURRICANE_HELENE/LANDSAT/ImageServer/WMSServer Data Download: https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/hurricane_helene_202409/landsat/

Date of Images: 10/11/2024, 10/12/2024 Summary: The Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at NASA's Jet Propulsion Laboratory and California Institute of Technology derived the disturbance maps using the OPERA Disturbance Alert from Harmonized Landsat Sentinel-2 (DIST-ALERT-HLS) products. The results posted here are preliminary and unvalidated results, primarily intended to aid the field response and people who want to have a rough first look at the surface disturbance extent. The ARIA-share website has always focused on posting preliminary results as fast as possible for disaster response. OPERA DIST-ALERT-HLS The Disturbance product (DIST) maps per pixel vegetation disturbance (specifically, vegetation cover loss) from the Harmonized Landsat Sentinel-2 (HLS) scenes. We provide the vegetation disturbance status (VEG-DIST-STATUS) and the maximum vegetation anomaly value (VEG-ANOM-MAX) layers. Images are provided from October 2, 2024. Each image consists of multiple MGRS tiles that were merged together for a composite image saved as a GeoTIFF file. VEG-ANOM-MAX Difference between historical and current year observed vegetation cover at the date of maximum decrease (vegetation loss of 0-100%). This layer can be used to threshold vegetation disturbance per a given sensitivity (e.g. disturbance of >20% vegetation cover loss). The sum of the historical percent vegetation and the anomaly value will be the vegetation cover estimate for the current year. GEN-ANOM-MAX Maximum spectral distance between a current year HLS scene reflectance and the composite reflectance of previous calendar years. Generic disturbance, as determined from the variations of the reflectance through the HLS scenes, is intended to delineate generic changes outside of the vegetation cover loss theme. The DIST-ALERT HLS products have these flags: For VEG-ANOM-MAX layers, 255 represents No Data and is based on the Fmask layer of the source HLS granule. For the GEN-ANOM-MAX layer, -1 represents "No Data" and is based on the Fmask layer of the source HLS granule. Suggested Use: VEG-ANOM-MAX 0 (White) - 100 (Red): Maximum loss of percent vegetation 255: No data GEN-ANOM-MAX 0 (White) - Variable (Blue): Maximum spectral distance compared to composite reflectance of previous calendar years -1: No Data Satellite/Sensor: MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/B satellites and Operational Land Imager 2 (OLI-2) on NASA's Landsat 9 satellite. Resolution: 30 meters Credits: NASA JPL-Caltech ARIA/OPERA Team The product contains modified Copernicus Sentinel data (2024) and is produced as part of the OPERA project, which is funded by NASA to address remote sensing needs identified by the Satellite Needs Working Group. Managed by NASA's Jet Propulsion Laboratory, OPERA funds and manages the DIST-ALERT-HLS product developed and produced by the Global Land Analysis and Discovery (GLAD) laboratory at the University of Maryland. Additional Information: The OPERA DIST-HLS products have been in production since January 2022, are freely distributed to the public via NASA's Land Processes Distributed Active Archive Center (LP DAAC), and can be downloaded through NASA's Earthdata search. For more information about the Surface Disturbance product suite, please refer to the DIST Product page: https://www.jpl.nasa.gov/go/opera/products/dist-product-suite/ For more information about the Caltech-JPL ARIA project, visit https://aria.jpl.nasa.gov For more information about the JPL OPERA project, visit https://www.jpl.nasa.gov/go/opera/ Data Download: https://aria-share.jpl.nasa.gov/20241010-Hurricane_Milton/DIST/ Esri REST Endpoint:

Dates of Images: November 4, 2025; November 2, 2025; October 30, 2025 Summary: The Advanced Rapid Imaging and Analysis (ARIA) and Observational Products for End-Users from Remote Sensing Analysis (OPERA) teams at the Jet Propulsion Laboratory, California Institute of Technology created maps of surface disturbance caused by Hurricane Melissa in Jamaica on October 28, 2025 using the OPERA Disturbance Alert from Harmonized Landsat Sentinel-2 (DIST-ALERT-HLS) products. The results posted here are preliminary and unvalidated results, primarily intended to aid the field response and people who wanted to have a rough first look at the surface disturbance. The ARIA-share website has always focused on posting preliminary results as fast as possible for disaster response. All information is provisional for use under emergency response guidelines. These data are provided with absolutely no warranty of any kind. Use at your own risk. OPERA DIST-ALERT-HLS The Disturbance product (DIST) maps per pixel vegetation disturbance (specifically, vegetation cover loss) from the Harmonized Landsat Sentinel-2 (HLS) scenes. We provide the maximum vegetation anomaly value (VEG-ANOM-MAX) layer. All provided layers have been temporally filtered to include only disturbance detected following the start of Hurricane Melissa (starting October 28, 2025). Images are provided as GeoTIFF files. Note: Artifacts caused by clouds and cloud shadows are present in the product. The DIST-HLS product will eventually be updated to address these issues as more cloud-free data becomes available. VEG-ANOM-MAX: Difference between historical and current year observed vegetation cover at the date of maximum decrease (vegetation loss of 0-100%). This layer can be used to threshold vegetation disturbance per a given sensitivity (e.g. disturbance of >=20% vegetation cover loss). The sum of the historical percent vegetation and the anomaly value will be the vegetation cover estimate for the current year. Layer values: 0-100: Maximum loss of percent vegetation (suggested color: white to red gradient) 255: No data (suggested color: transparent) Satellite/Sensor: MultiSpectral Instrument (MSI) on European Space Agency's (ESA) Copernicus Sentinel-2A/B satellites and Operational Land Imager 2 (OLI-2) on NASA's Landsat 8/9 satellite. Resolution: 30 meters The DIST-ALERT-HLS products included here have these flags: 255 represents ''No Data'' and is based on the Fmask layer of the source HLS granule. OPERA DIST-ALERT-HLS data availability: Note: some direct straight lines on the edges of domains or within the data may represent boundaries between satellites or satellite overpasses as this is a hybrid product from multiple distinct assets. The post-processed products are available to download at https://aria-share.jpl.nasa.gov/20251028_Hurricane_Melissa/DIST-HLS/ The OPERA DIST-HLS products have been in production since January 2022, are freely distributed to the public via NASA's Land Processes Distributed Active Archive Center (LP DAAC), and can be downloaded through NASA's Earthdata search. For more information about the Surface Disturbance product suite, please refer to the DIST Product page: https://www.jpl.nasa.gov/go/opera/products/dist-product-suite/ For more information about the GLAD project, visit https://glad.umd.edu/ For more information about the Caltech-JPL ARIA project, visit https://aria.jpl.nasa.gov For more information about the JPL OPERA project, visit https://www.jpl.nasa.gov/go/opera/ Product POCs: Alexander Handwerger (alexander.handwerger@jpl.nasa.gov) Cole Speed (cole.speed@jpl.nasa.gov) Mary Grace Bato (bato@jpl.nasa.gov) Ines Fenni (ines.fenni@jpl.nasa.gov) Credits: The product contains modified Copernicus Sentinel data (2025) and is produced as part of the OPERA project, which is funded by NASA to address remote sensing needs identified by the Satellite Needs Working Group. Managed by NASA's Jet Propulsion Laboratory, OPERA funds and manages the DIST-ALERT-HLS product developed and produced by the Global Land Analysis and Discovery (GLAD) laboratory at the University of Maryland. NASA JPL-Caltech-UMD ARIA/OPERA Team ================== Last Update 06 November 2025

Dates of Images: Post-Event: October 12, October 10, October 7, October 5, October 2, September 27 Pre-Event: September 20, September 22 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 Short Wave Infrared (SWIR) RGB is a product that is created using the SWIR, NIR, and Red 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. The Short Wave Infrared (SWIR) RGB is a product that can provides value in flood detection. Areas of water will appear blue, healthy green vegetation will appear as a bright green, urban areas in various shades of magenta, snow will appear as a bright blue/cyan, and bare soils being multicolor dependent on their makeup. Compare pre-event imagery to post-event imagery to identify potential flooding. 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: True Color: 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_202409_HURRICANE_HELENE/SENTINEL2/ImageServer/WMSServer Data Download: https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/hurricane_helene_202409/sentinel2/

The Observational Products for End-Users from Remote Sensing Analysis (OPERA) Land Surface Disturbance Alert from Harmonized Landsat Sentinel-2 (HLS) product Version 1 maps vegetation disturbance alerts that are derived from data collected by Landsat 8 and Landsat 9 Operational Land Imager (OLI) and Sentinel-2A, Sentinel-2B, and Sentinel-2C Multi-Spectral Instrument (MSI). A vegetation disturbance alert is detected at 30 meter (m) spatial resolution when there is an indicated decrease in vegetation cover within an HLS pixel. The Level-3 data product also provides additional information about more general disturbance trends and auxiliary generic disturbance information as determined from the variations of the reflectance through the HLS scenes. HLS data represent the highest temporal frequency data available at medium spatial resolution. The combined observations will provide greater sensitivity to land changes, whether of large magnitude/short duration or small magnitude/long duration. The OPERA_L3_DIST-ALERT-HLS (or DIST-ALERT) data product is provided in Cloud Optimized GeoTIFF (COG) format, and each layer is distributed as a separate file. There are 19 layers contained within the DIST-ALERT product. The layers for both vegetation and generic disturbance include disturbance status, loss or anomaly, maximum loss anomaly, disturbance confidence layer, date of disturbance, count of observations with loss anomalies, days of ongoing anomalies, and day of last disturbance detection. Additional layers are vegetation cover percent, historical percent vegetation cover, and data mask. See the Product Specification Document (PSD) for a more detailed description of the individual layers provided in the DIST-ALERT product. The OPERA project is funded by NASA’s Satellite Needs Working Group (SNWG) which provides data products developed to meet the needs of stakeholders from US government agencies. The OPERA_L3_DIST-ALERT-HLS product contains modified Copernicus Sentinel data (2020-2025). Processing Improvements/Changes * For DIST-ALERT granules processed prior to July 21, 2026, the GeoTIFF "Input_DIST-ALERT_granule" metadata field lists a single granule. From July 21, 2026 onward, multiple prior granules may be referenced to account for all recent HLS granules as when a granule with an earlier sensing time is made available after a granule with a later sensing time. In this case, the field contains a comma-separated list. This processing update also applies to the "Input_DIST-ALERT_granule" field under the “AdditionalAttributes” section in the cmr.json file. Known Issues * Additional usage constraints are provided under Section 5 of the Algorithm Theoretical Basis Document (ATBD).