Collaboratory maps Helene damage to speed recovery

After Hurricane Helene cut a destructive path through western North Carolina in September 2024, the North Carolina Collaboratory launched a project to provide spatial data to support disaster recovery and long-term resilience planning in the region.

The project used high-resolution aerial photography and lidar, a laser-based technology that generates precise 3D models of terrain and structures, across 13 of the hardest-hit counties.

“The high-resolution nature of these lidar elevation data allows you to identify individual power lines, mailboxes and fire hydrants,” said Jeffrey Warren, Collaboratory executive director. “You can even count individual Christmas trees and blueberry bushes. It’s an amazingly detailed dataset.”

The project came together quickly, thanks to a fortunate convergence of timing and budget flexibility. The Collaboratory was able to redirect $4 million in digital engineering funds, which had been appropriated in late 2023 by the North Carolina General Assembly, to meet the urgent need for post-storm mapping.

“These are data we’ll be using for years,” Warren said. “It’s not just about the research and analysis focused on recovery; it’s also about the research and analysis that will allow western North Carolina to be better prepared for the next storm, regardless of magnitude.”

Lidar image of Western NC before Helene. (Submitted photos)

Prioritizing the most impacted

A rigorous disaster impact analysis allowed the Collaboratory to direct resources to the 13 counties that needed them most: Ashe, Avery, Buncombe, Burke, Davie, Haywood, Henderson, Jackson, McDowell, Mitchell, Rutherford, Watauga and Yancey.

“We began by filtering for counties that had received a presidential disaster declaration,” said John Dorman, vice president and director of emergency and risk management at AECOM, a global infrastructure consulting company. “From there, we overlaid storm-specific inundation data with structural impact assessments to determine which counties experienced the most significant damage.”

With the counties selected, AECOM coordinated a team to conduct the data acquisition. Timing was critical. Flights were conducted in January through early March to capture “leaf-off” conditions, necessary as foliage obstructs both lidar returns and aerial imagery.

To ensure efficiency and avoid duplication, the Collaboratory focused on the targeted counties, while the N.C. Department of Public Safety managed the lidar collection for a broader western area.

“Partnering with the Collaboratory allowed us to do more and more efficiently,” said Gary Thompson, N.C. DPS assistant director for risk management and chief of the N.C. Geodetic Survey. The imagery will also fill a critical gap identified and requested by the impacted communities.

Thompson noted that the data will be used by the state transportation department, the state geological survey and private companies. It will be essential for programs like floodplain remapping, landslide risk assessment and real-time flood warning systems powered by over 600 water-level gauges across the state.

From data to action

As the data becomes available, counties are receiving hard drives with their regional datasets. The complete data collection will also be made publicly available through NC OneMap, the state’s geospatial data portal.

One of the Collaboratory’s key research partners, the UNC Institute for Risk Management and Insurance Innovation, will analyze the data to measure changes in the landscape and the built environment since 2017.

“This is the first time we’ll have such a complete ‘before and after’ model,” Warren noted. “Not only does this help quantify loss for FEMA recovery requests, but it’s also vital for future planning. We can simulate how future storms might behave in the changed landscape.”

Read more about the Collaboratory’s data collection project.