Reanalyzing and Identifying Tornado Damage Paths in Hard-to-Reach Areas of the Gulf Coast using High-Resolution Satellite Imagery

The Gulf Coast region is home to extensive wetlands and dense forests, presenting unique challenges for the National Weather Service (NWS) Weather Forecast Offices (WFOs) in obtaining ground-truth reports for traditional storm surveying. Complete and accurate damage assessments are essential for maintaining the integrity of NOAA Storm Data, NWS warning verification performance, and future research that depends on a reliable historical database. Recent advancements in spatiotemporal resolution of satellite imaging over the past decades have paved the way for new meteorological applications for remote sensing, such as post-storm damage survey analyses. This study represents the first attempt to reanalyze all potential and confirmed tornadoes in recent years in often inaccessible areas of southeastern Louisiana and southern Mississippi using high resolution satellite imagery. Potential tornadic storms were identified via archived local storm reports and radar analysis of days with tornado watches and warnings. Known tornadoes were also reexamined to validate prior storm surveys and supplement the database. The Normalized Difference Vegetation Index (NDVI) product was used to compute differences in pre-event and post-event imagery to indicate potential damage paths. Further analysis was then conducted using the highest resolution (30 centimeters) imagery available to make note of the possible peak intensity of the identified tornado. This approach allowed for detailed scrutiny of potential damage indicators of new and existing tornadoes. The use of the NDVI product and further high resolution satellite analysis from the past several years revealed previously unrecorded tornadoes not listed in NOAA Storm Data and discrepancies in the tracks of previously confirmed tornadoes. A significant proportion of these findings pertained to tornadoes tracking through inaccessible areas. These findings highlight the value of integrating satellite imagery with ground-based storm surveys to achieve a more comprehensive and accurate historical record of tornadoes. These efforts enhance the efficiency of damage assessment and also ensure that the unique strengths of both satellite imagery and ground-based storm surveys are leveraged to provide a more robust understanding of tornado events for future research. Additionally, this study emphasizes the importance of further investment in expediting remote-sensing data requests post-event and providing guidance on effectively incorporating satellite imagery into the tornado rating process so it is used consistently.