|Category 5 major hurricane (SSHWS/NWS)|
|Formed||August 21, 2024|
|Dissipated||September 4, 2024|
|(Extratropical after September 3)|
|Highest winds||1-minute sustained: |
160 mph (260 km/h)
|Lowest pressure||933 mbar (hPa); 27.55 inHg|
|Fatalities||157 confirmed, 103 missing|
|Damage||$82 billion (2024 USD)|
|Areas affected||Lesser Antilles, Hispaniola, the Bahamas, Florida (especially Volusia and Flagler counties), Bermuda|
|Part of the 2024 Atlantic hurricane season|
Hurricane Isaac was a long-lived, powerful and highly damaging hurricane that became the strongest storm to hit Florida since Michael in 2018, and the strongest to hit the Bahamas since Dorian in 2019. It was the tenth tropical depression, ninth named storm, fourth hurricane and second major hurricane of the 2024 Atlantic hurricane season.
Isaac developed from a tropical wave which moved off the coast of Africa during mid-August. Although initially hitting unfavorable conditions in the eastern Caribbean, Isaac was able to reach highly favorable conditions while passing through the Bahamas, rapidly intensifying to reach its peak as a Category 5 Atlantic hurricane early on August 27. It made landfall in Volusia County, Florida late the next day before heading out to sea and turning extratropical while located northwest of the Azores.
Effects from Isaac were catastrophic, with immense damage occurring in northeastern Florida aswell as the northern Bahamas. In preperation for the storm, a state of emergency was declared for the state of Florida, and mandatory evacuations were issued for the entire northeastern portion of the state. Throughout the duration of the storm, Isaac caused $82 billion dollars in damage and 157 confirmed fatalities, with a further 103 missing.
During mid-August, a vigorous tropical wave moved off of the coast of Africa, producing a broad area of showers and thunderstorms. Moving generally westward, the wave gradually organized under favorable conditions, and the low had gained enough organization by 08:00 UTC on August 21 to be classified as a tropical depression, west-northwest of Barbados. Continuing to organize further, the depression was able to intensify into a tropical storm later that day, being assigned the name Isaac.
Isaac made landfall in Saint Lucia early the next day before entering the eastern Caribbean at its initial peak intensity of 50 mph (80 km/h). Isaac encountered strong wind shear as well as a fairly high amount of dry air mixing into the storm, causing the tropical storm to become disorganized and briefly open up into a tropical wave early on August 23, although it was able to regain tropical storm status by the end of the day. Organizing a bit further, Isaac reached a secondary peak intensity of 45 mph (70 km/h) before making another landfall, this time in the mountainous terrain of Hispaniola. Isaac weakened to a tropical depression overland, although it was able to retain its status as a tropical cyclone, albeit barely, as it exited land. By now, the system had began to move generally towards the northwest.
After exiting Hispaniola, Isaac encountered favorable conditions while passing through the Bahamas, causing it to quickly re-intensify into a tropical storm. Amid a highly conducive environment that promoted quick intensification, as well as the storms small size which helped cause quick fluctuations in strength, Isaac underwent rapid deepening while passing through the northern Bahamas, becoming a hurricane early on August 26. Isaac continued to rapidly intensify throughout the day, culminating in reconnaissance aircraft finding that Isaac had achieved a peak intensity of 160 mph (260 km/h) and a pressure of 933 mbar (hPa; 27.55 inHg), making it a Category 5 hurricane on the Saffir-Simpson hurricane wind scale. Following this, Isaac began to undergo an eyewall replacement cycle, weakening to a strong Category 4 hurricane as it started to make a counter-clockwise loop towards the coast of the United States. Isaac continued to gradually weaken as it moved closer and closer to the eastern shore of Florida, and satellite estimates indicated Isaac made landfall in Volusia County, Florida late on August 28 with maximum winds of 115 mph (185 km/h).
Almost immediately after landfall, Isaac began to turn back towards the east, moving off of land as a minimal hurricane during mid-day on August 29. Moving to the northeast, Isaac began to gradually intensify while slowly gaining size and moving out to sea, attaining a quaternary peak on September 1 located south of Bermuda with winds of 115 mph (185 km/h).
Isaac began to weaken yet again not long after, dropping below major hurricane status later that day. During September 2, Isaac began to accelerate to the northeast as it began to turn post-tropical, with the windfield of the storm significantly expanding as it continued to weaken. Early on September 3, Isaac weakened below hurricane intensity just before becoming a strong gale-force extratropical low to the west-northwest of the Azores. Speeding off into the northern Atlantic, the post-tropical remnants of Isaac were absorbed into a developing cold-core low early on September 4.
Following the designation of Tropical Depression Ten while east of the island, the National Hurricane Center (NHC) immediately issued a tropical storm warning for the island, which had still been recovering from the effects of Hurricane Alex two years prior. Prime Minister Allen Michael Chastanet advised the residents of the country to stay home while the storm passed. All public services were closed in preparation for the storm.
Although Isaac was expected to dodge the island to the south, the broad nature of the storm at the time permitted the NHC to issue a tropical storm watch for the island. Most public services were closed in advance of the storm's passage, excluding critical services such as hospitals and governmental offices.
Tropical storm warnings were issued for Hispaniola following the storm's regeneration into a tropical cyclone, with the governments of both Haiti and the Dominican Republic advising residents to stay in their homes and for residents in lower-lying areas to evacuate to higher ground. The Dominican Republic would declare a state of emergency not long after for the southwestern part of the nation, with a mandatory national curfew implemented in anticipation of the storm's passage through the country.
While inland over Hispaniola, the NHC issued a tropical storm warning for the entirety of the Bahamas, later being upgraded to a hurricane warning as the storm rapidly intensified while passing through the country. Evacuations to local hurricane shelters were recommended for the northern part of the country by the Bahamian government following the issuance of hurricane warnings. The Bahamian government followed this up with a declaration of a state of emergency, as catastrophic impacts were expected from the system.
Following the designation of Isaac as a hurricane, the NHC issued a hurricane watch for eastern Florida, later being upgraded to a hurricane warning.
In response to this, the government of Florida issued a state of emergency for the following counties:
- Volusia county
- Brevard county
- Flagler county
- Seminole county
- Orange county
- Lake county
- Putnam county
- Marion county
All major sporting events were canceled or postponed in the state following the issuance of a hurricane warning, and all businesses were closed in advance of the storm. Additionally, mandatory evacuations were issued for the aforementioned counties.
Following the upgrade of the storm to a major hurricane, the local government issued a statewide state of emergency, as catastrophic damage was expected from the storm. Additionally, the aforementioned counties were declared federal disaster areas by the national government.
Although Isaac was expected to pass south of the island, a tropical storm watch was issued due to the large size of the storm as it began to move towards the island before being upgraded to a tropical storm warning soon after. Schools and businesses were closed in advance of the storm.