Effects of Deadly California Debris Flows Seen in Before/After Images from NASA's UAVSAR

Extreme winter rains in January 2018 following the Thomas Fire in Ventura and Santa Barbara Counties caused severe debris flows, resulting in significant loss of life and considerable property damage in the town on Montecito, just east of Santa Barbara. NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) airborne radar platform detected changes caused by the debris flows between two images acquired on Nov. 2, 2017, and Feb. 5, 2018. An enhanced image pair (top left) shows disturbed areas in orange. In areas of severe surface disruption from the fire scar and debris flows the two image pairs can't be matched and decorrelate (top right). In the middle panels, the radar images are overlaid on the structure damage map produced by the County of Santa Barbara. The fire scars and damage correspond well with the risk map (lower left) and damage map (lower right). With an operational system, products such as these have the potential to augment information available for search and rescue, and for damage assessment for government agencies or the insurance industry. Radar has the advantage of being available in all weather conditions, as it can image through clouds.

NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), developed and managed by the Jet Propulsion Laboratory, Pasadena, California, can record changes on the ground beneath the aircraft that occur between multiple flights, which take exactly the same flight path. The instrument is used to monitor how volcanoes, earthquakes, and other natural hazards are changing Earth.

The JPL UAVSAR team collected and processed the imagery for Principal Investigator Andrea Donnellan who performed the analysis. She has been conducting ground change research using UAVSAR in this and other regions of California since 2009.