Hurricane Ida brings flooding and power outages to Louisiana

Hurricane Ida made landfall as a Category 4 hurricane near Port Fourchon, Louisiana, on August 29^th, 2021 [1]. While New Orleans’ levees survived [2], damage to major transmission lines left nearly the entire city—and about 1 million people statewide—without power [3]. Coming within 30 miles of downtown New Orleans on the 16^th anniversary of Hurricane Katrina, Ida subjected the city to greater wind damage than Katrina, which was a Category 3 storm when it made landfall in Louisiana. Ida also tracked further west than Katrina, putting New Orleans in the stronger east and northeast parts of the hurricane’s circulation [4]. Hundreds of Louisiana residents have been displaced and officials have advised them not to return until roads have been cleared and power lines have been repaired, which may take weeks [5]. Areas of Terrebonne, Lafourche, Jefferson, and Plaquemines Parishes are without clean or running water and under boil water notices [6].

AER’s FloodScan system automatically maps large-scale inland flooding daily across North American, Africa, and South America from cloud-penetrating passive microwave satellite observations. FloodScan first detected persistent inland flooding from Ida on August 30^th. The images below show maximum flood extent and depth mapped by FloodScan between August 30^th and August 31^st. A GIS-compatible package of the complete FloodScan product suite covering Ida’s impact on Louisiana is available for purchase through the AER store.

As of September 1, AER’s experimental FloodLoss algorithm estimates that flooding from Ida affected 32,123 buildings statewide with associated damages ranging from 600 million to seven billion dollars. FloodLoss combines FloodScan data with data from the Microsoft Building Footprint Database [7] to assess the number and size of flooded buildings. Real estate valuations and historical National Flood Insurance Program (NFIP) Data [8] are then used to assign loss values. The FloodLoss estimate of total loss includes only flood-affected buildings and not losses due to wind, storm surge, etc.

_{[1] https://www.nhc.noaa.gov/archive/2021/al09/al092021.update.08290645.shtml}

_{[2] https://www.npr.org/2021/08/31/1032804634/new-orleans-levees-hurricane-ida-flooding}

_{[3] https://www.npr.org/2021/08/30/1032549785/heres-the-latest-on-ida-the-tropical-storm-thrashing-the-gulf-coast}

_{[4] https://www.accuweather.com/en/hurricane/where-ida-stands-worst-hurricanes-to-hit-louisiana-us/1010288}

_{[5] https://www.washingtonpost.com/national/southeast-louisiana-residents-desperate-for-food-power-water-and-help-in-idas-aftermath/2021/08/31/9696a20e-0a84-11ec-9781-07796ffb56fe_story.html}

_{[6] https://www.houmatoday.com/story/news/local/2021/08/31/hurricane-ida-louisiana-residents-can-return-damaged-parishes/5664050001/}

_{[7] https://www.microsoft.com/en-us/maps/building-footprints}

_{[8] https://www.fema.gov/openfema-data-page/fima-nfip-redacted-claims}