Hurricane Isaac originated from a tropical wave that moved off the western coast of Africa on August 17 . Moving generally westward , the low-pressure area initially did not have a well-defined center until three days later . Convection associated with the system organized and intensified , and the tropical wave quickly strengthened into a tropical depression . In favorable conditions , the depression was upgraded to Tropical Storm Isaac by the National Hurricane Center ( NHC ) on August 21 . Quickly accelerating westward due to a subtropical ridge located to the northwest , Isaac later moved past the Lesser Antilles between Guadeloupe and Dominica by August 23 , where it caused numerous mudslides and power outages . Maintaining tropical storm intensity , Isaac later made its first landfall on the southern coast of Haiti early on August 25 as a result of southeast flow . There , the storm directly killed 24 people , worsening conditions still remaining after the 2010 Haiti earthquake
2010 Haiti earthquake
2010 Haiti earthquake
Effects of Hurricane Isaac in Florida