By Elisa Jiménez Alonso
In the US, close partnerships between National Aeronautics and Space Administration (NASA), United States Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), and Federal Emergency Management Agency (FEMA) help improve flood response and recovery when disasters strike. Earth observation data from NASA satellites offer invaluable information that can guide disaster aid in affected communities by providing products tailored to the needs of the respective agency. Such collaborations have helped thousands of people recover from flood disasters.
Louisiana’s historic flood
In 2016, Louisiana was battered by a 500-year deluge that led its governor to declare a state of emergency. The most severely affected areas received totals 61cm of rain with peaks of almost 80cm in Watson, near Baton Rouge. The record-breaking rainfall began on August 12 and FEMA soon reached out to NASA with a request to assess the potential disaster that was developing.
Using the Global Flood Monitoring System (GFMS), which uses data from the Global Precipitation Measurement satellite mission, NASA provided FEMA numbers about the potential for flooding and predictions of inundation for the coming days. USGS also activated the International Charter on Space and Major Disasters to access additional satellite imagery. Using all these data, experts at NASA’s Jet Propulsion Lab (JPL) were able to compare before and after images of affected areas. Soon, FEMA had flood extent and flood proxy maps thanks to validation from aerial imagery from NOAA and water marks from USGS.
Speaking to NASA Glen Russell, remote sensing coordinator at FEMA, said “We estimated that Louisiana would have about 27,000 damaged homes, but it was through the acquisition of SAR data [synthetic aperture radar] and other remotely sensed data that we were able to see that that was a much larger impact than we had forecast.” It was thanks to the combination of remotely sensed data that FEMA decided to increase the resources they had sent to Louisiana, helping many families find shelters and new homes.
2017’s record-breaking hurricane season
Last year saw several major deadly and destructive hurricanes in the Atlantic basin. Six of the 17 storms developed into major hurricanes, hurricanes with a Saffir-Simpson scale category of 3 or higher. In August and September, hurricanes Harvey, Irma, and Maria set all kinds of records during a hurricane season that produced both the highest total accumulated cyclone energy on record and the highest number of major hurricanes since 2005.
During this challenging time, USGS provided large amounts of remotely sensed data at no cost through its Hazard Data Distribution System (HDDS) to analyse the extent, severity, and evolution of major hurricanes Harvey, Irma, and Maria. USGS staff worked around the clock keeping the portal up to date. Over 15,000 images were downloaded and requests came from 48 government agencies, including the US Senate, Department of Homeland Security, and the Centers for Disease Control. FEMA used HDDS data about roads and infrastructure in Houston to direct rescue efforts during Hurricane Harvey.
The access to such high-quality data in a fast and uncomplicated manner has made it possible to produce and distribute maps that help disaster management authorities make decisions and prove invaluable during rescue efforts.