The Global Precipitation Measurement (GPM) mission provided an analysis of the storms that led to widespread flooding in Louisiana in August 2016. The storm might have turned into a tropical cyclone, except that it formed over land, which limited its moisture supply. The GPM satellite looked beneath the clouds to detect curved rain bands near the storm's center. Over water, this structure would form an eyewall. Trapped under upper level high pressure, the storm slowed, causing recording flooding for Louisiana. Data from GPM and other satellites provided estimates of more than 20 inches of rain across Louisiana from August 8-15. These events challenge numerical weather models when the rain occurs with large amounts of moist, rising air and no definitive steering winds. Combining rainfall estimates with hydrological models can improve estimates of when and where major floods occur.