Supporting hurricane response in Puerto Rico with aerial imagery

When Hurricane Fiona hit Puerto Rico in September of 2022, resultant flooding and landslides caused significant damage on the island. Local and federal government agencies and insurance companies needed to determine the location and extent of this damage in a timely manner for restoration and assessment. With such a large area of potential impact—Puerto Rico is about 3,500 square miles in area—evaluating the aftermath was no small feat.

The approach: Aerial imagery
One of the most efficient ways to assess damage across large expanses is to acquire aerial imagery from manned, fixed-wing aircraft. About a week and a half after Hurricane Fiona hit, the U.S. Department of Agriculture (USDA) sent a task order for imagery over the entire island to Missouri-based geospatial provider Surdex Corp., which proceeded to design and execute the imagery acquisition efforts.

Rapid delivery of aerial imagery for Fiona’s response efforts was ultimately made possible through a few key factors, supported by rapid communication:

• An existing General Services Administration (GSA) contract that allowed a rapid contract response through the USDA PINE Ad Hoc and Disaster Support Programs
• Conducting acquisition flights during all clear opportunities
• Quick, minimal processing of imagery and upload to a web service

USDA PINE Ad Hoc and Disaster Support Programs
In 2022, the USDA established its five-year PINE Aerial Imagery Blanket Purchase Agreement (BPA) contract, selecting seven geospatial providers to facilitate the acquisition of aerial imagery through five different programs, each with unique purposes and specifications. Through the Ad Hoc and Disaster Support Programs, the USDA sent a task order to Surdex for 4-band (red, green, blue, near infrared) 30cm post-hurricane imagery over Puerto Rico with “relaxed” specifications. While most PINE programs require a minimum 30-degree sun angle and no cloud cover, this task order allowed a minimum 25-degree sun angle and up to 10 percent cloud cover to expedite acquisition.

Acquiring data on a perpetually cloudy island
Even with relaxed cloud cover specifications, it is very challenging to acquire imagery over Puerto Rico because as a Caribbean Island, it is prone to persistent clouds, especially in the higher elevations and rainforest areas of the island. The aerial imagery acquisition flights began mid-October 2022, and through taking advantage of every clear weather opportunity, acquisition was completed in January of 2023. To further facilitate rapid acquisition, in lieu of traditional ground survey methods, locational information for the image sensor was corrected using a base station, Continuously Operating Reference Stations (CORS) and existing survey points from a prior project.

Road flooding in Puerto Rico

Quick upload
As the imagery was acquired, it was minimally processed and then posted to a web service within 10 days of each flight. To expedite delivery of the imagery, the initial processing did not include full rectification or color correction; those steps were completed later, after the entire project data set had been acquired. This preliminary imagery enabled government agencies such as the Federal Emergency Management Agency (FEMA) to begin using the imagery as quickly as possible for critical recovery efforts. FEMA uses imagery to perform pre- and post-disaster comparison to examine essential infrastructure features that might be damaged, such as power and water plants, bridges and roads.

Public/private collaboration
This project demonstrates how collaboration between private and public sectors results in efficient response to natural disasters. First, the government defines its objective and any specifications, then the private sector designs a solution that meets the government’s needs.

Through the PINE contract, the USDA and Surdex were able to work together and successfully and quickly provide the aerial imagery that federal agencies such as FEMA needed to respond to hurricane Fiona’s aftermath. The Ad Hoc and Disaster Support Programs have proven to be a valuable tool for supporting the people of the United States when natural disasters strike.

Tracy Ray, CMT-GIS, is the technical writer at Surdex Corporation. She started as an orthoimagery technician at Surdex before transitioning to her current role. She has a B.A. in Geography from the University of Nebraska–Lincoln and an M.A. in Geography from the University of Missouri–Columbia.