 Prior to the advent of modern tropical cyclone tracking technology , notably satellite imagery , many hurricanes that did not affect land directly went unnoticed , and storms that did affect land were not recognized until they made landfall . As a result , information on older hurricane seasons was often incomplete . Modern @-@ day efforts have been made and are still ongoing to reconstruct the tracks of known hurricanes and to identify initially undetected storms . In many cases , the only evidence that a hurricane existed was reports from ships in its path . However , judging by the direction of winds experienced by ships , and their location in relation to the storm , it is possible to roughly pinpoint the storm 's center of circulation for a given point in time . This is the manner in which four of the seven known storms in the 1860 season were identified by hurricane expert José Fernández Partagás 's reanalysis of hurricane seasons between 1851 and 1910 . Partagás also extended the known tracks of three other hurricanes previously identified by scholars . The information Partagás and his colleague uncovered was largely adopted by the National Oceanic and Atmospheric Administration 's Atlantic hurricane reanalysis in their updates to the Atlantic hurricane database ( HURDAT ) , with some slight adjustments . HURDAT is the official source for such hurricane data as track and intensity , although due to a sparsity of available records at the time the storms existed , listings on some storms are incomplete . 
