Table 1: 24-hour rainfall recorded at different locations in Alabama, Florida and Georgia states and JBA return period estimate in years. Folley Creek, near Dixie in Alabama, saw rainfall totals of 11.81 inches (300mm), which could indicate a return period of up to 200 years for the rainfall received in a single day from Hurricane Sally. At Brewton, Alabama, the 24-hour accumulated rainfall of 13.64 inches (346mm) gives an estimated return period of 250 years (Table 1). Using daily historical rainfall data, JBA has generated return period estimates for the five sites with highest recorded rainfall in Alabama and Florida (Table 1). The maximum recorded rainfall accumulated over a 24-hour period between 16 and 17 September 2020 was 13.64 inches (346mm), recorded near Brewton in Alabama state. Purple represents pluvial (surface water) flood and light blue represents fluvial (river) flood. Extreme rainfallįigure 1: Extract of the JBA Flood Footprint for Hurricane Sally (Source: JBA Risk Management). While still projected to bring continued rainfall and further flooding remains possible in the Northern states, it is Hurricane Sally’s impact along the gulf coast that will be its most damaging legacy. Its forward progression (translational speed) increased and it rapidly veered inland across Georgia and North Carolina. Through late Wednesday and Thursday morning (17 September), the hurricane’s wind speed dropped significantly as it was downgraded to a tropical storm. Cumulative rainfall levels in cities across the Alabama/Florida border exceeded 24 inches in a 48-hour period, leaving 500,000 homes and businesses without power (Reuters 2020). Storm surge occurred in coastal towns such as Orange Beach and Gulf Shores, AL, as well as Pensacola, FL, where a surge of over 5ft (1.5m) was observed, causing damage to cars, boats and properties. The most significant damage has been witnessed along the Alabama and Florida gulf coasts where the storm made landfall (NYTimes, 2020a). As it slowly progressed across the Florida Panhandle, the tropical depression brought extreme levels of rainfall, resulting in significant and widespread pluvial, fluvial and coastal flooding. Hurricane Sally made landfall on Wednesday 16 September as a Category 2 hurricane near Gulf Shores, Alabama. All updates will also give you the option to unsubscribe. If you would like to unsubscribe at any time please contact us at with the subject line Opt-out or call JBA Risk Management Marketing on 01756 799919. We will not share your data with any third party. We will securely store the data that you share.
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