Reconstructing tropical cyclone impacts in Madagascar during the 19th-century using missionary and colonial sources

Attempts at document-based historical climate reconstructions for Africa south of the Sahara are hampered by the comparatively recent development of written cultures in many regions. Exceptions are those areas which were either subject to colonial governance or had a history of contact with European colonial powers. Historical climate information for the island of Madagascar can be derived from narratives within diaries, letters and reports produced by botanists, visiting diplomats and various groups of British, French and Norwegian missionaries. These sources supply information on general weather conditions and extreme events. In this paper, we use such documentary sources to reconstruct cyclones and tropical storms that made landfall on Madagascar during the middle to late 19th century. We pay particular attention to identifying the impacts of tropical cyclones, as described in historical accounts from the central highlands and coastal regions of Madagascar, and use this information to reconstruct the approximate pathways of individual storm events. We also apply a modified version of the methods developed by Boose (2004) and Chenoweth (2007) to classify the severity of each cyclone. Our results are compared against the record of southern Indian Ocean tropical storms included within the NOAA IBTRACS database.