Pinpointing Where the Lights Went Out in Puerto Rico

After Hurricane Maria tore across Puerto Rico, it quickly became clear that the destruction would pose daunting challenges for first responders. Most of the electric power grid and telecommunications network was knocked offline. Flooding, downed trees, and toppled power lines made many roads impassable.

These before-and-after images of Puerto Rico’s nighttime lights are based on data captured by the Suomi NPP satellite. The data were acquired by the Visible Infrared Imaging Radiometer Suite (VIIRS) “day-night band,” which detects light in a range of wavelengths from green to near-infrared, including reflected moonlight, light from fires and oil wells, lightning, and emissions from cities or other human activity.

One pair of images shows differences in lighting across the entire island, while the other pair shows lighting around San Juan, capital of the commonwealth. One image in each pair shows a typical night before Maria made landfall, based upon cloud-free and low moonlight conditions; the second image is a composite that shows light detected by VIIRS on the nights of September 27 and 28, 2017. By compositing two nights, the image has fewer clouds blocking the view. (Note: some clouds still blocked light emissions during the two nights, especially across southeastern and western Puerto Rico.) The images show widespread outages around San Juan, including key hospital and transportation infrastructure.

See https://earthobservatory.nasa.gov/IOTD/view.php?id=91044&eocn=home&eoci=iotd_image