2024 LANDSLIDE RESPONSE EFFORTS OF THE VERMONT GEOLOGICAL SURVEY: LESSONS LEARNED SINCE 2023 AND GOALS FOR PROACTIVE HAZARD PLANNING

On July 10-11, 2024, one year to the day after catastrophic flooding and landslides associated with the Great Vermont Flood of July 2023 impacted the state, heavy precipitation from the remnant tropical cyclone Beryl delivered up to 8 inches of rainfall in various locations across Vermont. Like the summer storm of 2023, this storm destroyed private residences and public infrastructure, resulted in a federal disaster declaration, and prompted months of active engagement by the Vermont Geological Survey (VGS). Between 2023 and 2024, the VGS engaged in over 150 slope stability evaluations and has partnered with Vermont Emergency Management (VEM) to support 16 residential buyout applications through the Federal Emergency Management Agency (FEMA).

There are significant differences between the 2023 and 2024 landslide-triggering events including storm track and the total number of landslides caused. The 2023 precipitation event was centered on the steep slopes of the north-south trending Green Mountains, whereas the 2024 storm path tracked west-east across the northern segment of the mountain range. For both events there was a tight spatial correlation between landslide site evaluation locations and the paths of heaviest rainfall. Still, more classified landslides were triggered in 2023, while impacts in 2024 were predominantly heavily eroded drainage features such as ditches, small brooks, and gullies. While the impacts of these recent storms varied, they emphasize a critical need for consistent and effective interagency communication during the response and recovery phases of landslide triggering events.

As extreme weather events are predicted to increase across the Northeastern United States, the VGS seeks to increase our ability to provide Vermonters with reliable and accessible landslide hazard preparedness resources. For example, the VGS and our partners are leveraging the insights gained from these storms and statewide quality-level 1 (8 points/m²) LiDAR-derived elevation data collected in 2023 to fill data gaps in our landslide inventory and develop a comprehensive landslide susceptibility model. Through this effort and interagency collaboration, the VGS aims to take a proactive approach to landslide preparedness and mitigation in addition to our active role in post-storm response.