Hurricane Isaac was a deadly and destructive tropical cyclone that came ashore the U. S. state of Louisiana during August 2012. The ninth named storm and fourth hurricane of the hurricane season. Though the system intensified into a storm shortly thereafter, high wind shear initially prevented much change in strength. An intensification of the ridge of pressure to the cyclones north caused it to turn westward over the Florida Keys by August 26. The system gradually weakened inland, but still produced a widespread tornado outbreak across the middle of the country before dissipating into an open low early on September 1. Prior to becoming a hurricane, Isaac produced flooding rainfall across much of the Lesser and Greater Antilles, particularly hard hit was the island of Haiti, where 24 people lost their lives. Overflowing rivers led to significant structural damage and many roadways were washed away, while gusty winds and rainfall were reported in Cuba, damage was limited to a few buildings. In Florida, Isaac produced several inches of rainfall, leading to flooding, strong winds knocked out power to thousands, and waves along the coast caused minor beach erosion. The most severe effects of the storm, however, occurred in Louisiana following the upgrade to hurricane intensity. Tropical storm-force sustained winds, with well over hurricane strength, knocked out power to hundreds of thousands. Many dams along the coastline were briefly over-topped, though they did not break completely and were later pumped to prevent failure. Gusts near hurricane intensity and heavy rainfall led to widespread power outages in the neighboring state of Mississippi. As an extratropical cyclone, Isaac produced torrential rains across Arkansas, flooding streets and homes. Strong winds contributed to downed lines and trees, overall, Isaac caused $2.39 billion in damage and led to 41 fatalities. A tropical wave crossed the west coast of Africa between August 15 and August 16, later that day and early on August 17, the system began developing more convection, while located just west of Sierra Leone. As a result, the National Hurricane Center began monitoring the system in the Tropical Weather Outlooks, thereafter, further organization briefly halted, though by early on August 18, associated convection became more concentrated. On the following day, the reached a high probability of tropical cyclogenesis. Between early on August 19 and early on August 21, minimal structural improvement occurred, conditions were generally favorable for further intensification, with the exception of northeasterly wind shear
Image: Isaac Aug 28 2012 1630Z
Visible satellite image during the early morning of August 29 of Isaac as it slowly moves over the northern Gulf of Mexico.
Waves from Tropical Storm Isaac battering the coast of the Dominican Republic.
New Orleans experienced hurricane force winds, but escaped the major flooding suffered by some other parts of southeast Louisiana.