2025 OEFS: Flood_Planet

Abstract

Hurricane Helene (September 26, 2024) had a profound impact on lives and livelihoods across the Southeastern United States, especially in western North Carolina where the storm hit hardest. The storm’s impact on agriculture alone is estimated by North Carolina’s budget office at $4.9 billion. In this project, we aim to utilize the fine-scale resolution and quick return interval of PlanetScope satellite data to quantify the impact of Hurricane Helene on western North Carolina. We used PlanetScope imagery and ENVI 6.0 to examine NDVI and land cover change for three sites, one agricultural, one urban, and one forested, in September and October of both 2023 and 2024. We found a large decrease in forest cover at two of our sites after the hurricane and a corresponding increase in bare ground at the same sites. We also observed a significant decrease in NDVI of water bodies, indicating large amounts of sediment in water. This study provides a great launch point for future studies such as repeating this analysis with imagery from a larger time frame, ground-truthing observations, taking forest measurements to estimate the amount of carbon lost from forests during the storm, or comparing forest cover loss to slope.

satellite view of three study locations — **Fig. 1.** Map of our three sites in North Carolina, USA

Line graph of NDVI Fall Change: Forest. 2023 light green line foes down from a little under 0.85 to 0.55 in a series of steps from late september to late december. 2024 dark green line almost straight decline from under 0.85 to 0.5 from late september to late december. — *Fig. 2a: NDVI calculations for Leicester, NC*

Line graph of NDVI Fall Change: Fields and Dry Fields. — *Fig. 2b: NDVI calculations for Leicester, NC*

Line graph of NDVI Fall Change: Buildings and Water — *Fig. 2c: NDVI calculations for Leicester, NC*

Line graph of fall change in NDVI for Asheville, NC, for 2023 and 2024 — *Fig. 3: NDVI calculations for Asheville, NC*

Blue topographical image — *Fig. 4: NDVI change for Asheville, NC between September and October 2024*

False color satellite image with legend — **Fig. 6.** Land cover classes for Asheville, NC, in September 2024

Bar graph of Asheville NC, change in landcover (supervised classification) — *Fig. 8. Change in percent of Asheville, NC, image covered by land cover types*

bar graph of lake lure supervised classification 2023 vs. 2024 — **Fig. 9.** Change in percent of Lake Lure, NC, image covered by land cover types

satellite and false color images of Lake Lure, NC — **Fig. 10.** Land cover change at Lake Lure, NC, between September and October 2024

Using PlanetScope to Quantify Hurricane Helene’s Impacts in North Carolina, USA

Abstract