USING GOOGLE EARTH HISTORICAL IMAGES TO ASSESS IMPACT OF HURRICANES IN THE BAHAMAS

Historical satellite imagery is related to information about intensity and pathways of hurricanes in the Bahamas to assess amount and style of modifications by major storms during this time of globally rising sea level. Examples include severe beach erosion, damage to roads, washovers of beach sand and rock boulders into interior settings, and conversion of coastal lakes to lagoons with creation of new inlets. This work specifically evaluates the usefulness of Google Earth historical imagery for documenting hurricane impact.

Google Earth historical imagery has been available since about 2001, with variable coverage throughout the Bahamas. Seven major hurricanes (i.e., sustained winds >111 mph or Category 3 and higher on the Saffir-Simpson scale) impacted the Bahamas during this time: Frances (2004), Ike (2008), Irene (2011), Sandy (2012), Joaquin (2015), Matthew (2016), and Irma (2017). Google Earth imagery of all islands impacted by these hurricanes was examined, and some of the most impressive examples from hurricanes Ike, Joaquin, Matthew, and Irma on San Salvador and Great Inagua islands are documented and supplemented by field photos and high-resolution drone images.

Google Earth proved to be a useful tool for such documentation, but the variable timing of image acquisition is not ideal for recording hurricane impact before natural and human-assisted recovery processes begin. Google Earth images also have limited resolution compared to high-resolution drone images, which are particularly useful, but can be difficult and expensive to acquire. Generating drone images also is dependent upon the ability to travel to impacted areas in a timely manner after major storms. Google Earth was especially useful for historical documentation of examples of storm impact that were previously identified in the field, but it was generally challenging to locate new examples, which could potentially be examined on site in the future. Overall, our methodology and results represent an important means for documenting and communicating information about vulnerability to hurricanes with local residents, developers, and other decision- and policy-makers in the Bahamas.