Tropical Storm Isaac (2012)

Hurricane Isaac was a deadly and destructive tropical cyclone that came ashore in the U.S. state of Louisiana during August 2012. The ninth named storm and fourth hurricane of the annual hurricane season, Isaac originated from a tropical wave that moved off the west coast of Africa on August 16. Tracking generally west, a broad area of low pressure developed along the wave axis the next day, and the disturbance developed into a tropical depression early on August 21 while several hundred miles east of the Lesser Antilles. The system intensified into a tropical storm shortly thereafter, but high wind shear initially prevented much change in strength.

Isaac tracked between Guadeloupe and Dominica late on August 22, and then turned towards the west-northwest and entered a region favorable for intensification; it passed over Haiti and Cuba at strong tropical storm strength. A ridge of high pressure to Isaac's north intensified and turned it westward over the Florida Keys by August 26, and Isaac entered the eastern Gulf of Mexico the next day. Gradual intensification occurred, in which the system reached its peak intensity as a Category 1 hurricane, with 1-minute sustained winds of , prior to making two landfalls, both at the same intensity, on the coast of Louisiana during the late evening hours of August 28 and early morning hours of August 29, respectively. The system gradually weakened once inland, but still produced a widespread tornado outbreak across the middle of the country before dissipating into an open low early on September 1.

Before it became a hurricane, Isaac produced flooding rain 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, preventing aid to the affected area. Gusty winds and rainfall were reported in Cuba, but damage was limited to a few buildings. In Florida, Isaac produced several inches of rain, 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 after the storm was upgraded to hurricane intensity.

Tropical storm-force sustained winds, with gusts well over hurricane strength, knocked out power to hundreds of thousands, and heavy rain led to flooding. Many dams along the coast were briefly over-topped, though they did not break completely and were later pumped to prevent failure. Gusts near hurricane intensity and heavy rain also led to widespread power outages in the neighboring state of Mississippi, and parts of Alabama recorded nearly of rain. As an extratropical cyclone, Isaac produced torrential rains across Arkansas, flooding numerous streets and homes, and damaging many crops across the region. Strong winds felled downed lines and trees. Overall, Isaac caused $3.11 billion (2012 USD) in damage and led to 41 fatalities.

Meteorological history

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 (NHC) began monitoring the system in the Tropical Weather Outlooks (TWOs). Thereafter, further organization briefly halted, though by early on August 18, associated convection became more concentrated. On the following day, the wave had a "high" probability of undergoing tropical cyclogenesis. Between early on August 19 and early on August 21, minimal structural improvement occurred, despite increases in development probability. By August 21, the system developed enough organization for the NHC to initiate advisories on Tropical Depression Nine; at the time, the depression was about east of the Leeward Islands, moving west to the south of a large ridge. Conditions were generally favorable for further intensification, except for northeasterly wind shear.

Late on August 21, a Hurricane Hunters mission observed flight-level winds of , and on this basis the NHC upgraded the depression to Tropical Storm Isaac. Despite its intensification, the storm was disorganized with its center north of the deepest convection. The circulation became elongated early on August 22, and the storm absorbed drier air in its northeast quadrant. Later that day, the low pressure area passed just south of Guadeloupe and into the Caribbean Sea. Dry air continued to hinder convection, although Isaac gradually became better organized. By late on August 24, the Hurricane Hunters observed a well-defined circulation; by that time, however, the strongest convection was moving over Hispaniola. An eye feature developed early on August 25, and Isaac attained winds of before crossing the southwest peninsula of Haiti.

While moving across Haiti, the circulation of Isaac became disrupted while the convection became disorganized. Continuing to the northwest, the storm moved along the north coast of Cuba. Convection increased over the center by early on August 26, and Isaac re-intensified slightly while entering the Straits of Florida. However, continued dry air prevented the inner core of convection from developing. Hurricane Hunters reported that a ragged eye developed multiple times, but the feature did not persist. The storm tracked northwestward across the Gulf of Mexico due to a subtropical ridge to its north. Although the barometric pressure continued to decrease, Isaac remained a large storm, which contributed to the lack of strengthening. At about 1620 UTC (11:20 a.m. CDT) on August 28, Isaac attained Category 1 hurricane status about south-southeast of the mouth of the Mississippi River, based on data from the Hurricane Hunters.

After further intensification, Isaac made landfall at 2345 UTC (6:45 p.m. CDT) on August 28, just southwest of the mouth of the Mississippi River with winds of . The eye moved back over water shortly thereafter, crawling just offshore of southeastern Louisiana (with little change in strength) before Isaac struck Louisiana again just west of Port Fourchon at 0715 UTC (2:15 a.m. CDT) on August 29. Hours after it made landfall, Isaac's eye became less circular and was open on the western side. Around 1900 UTC (2:00 p.m. CDT) on August 29, the hurricane weakened into a tropical storm as it slowly moved through Louisiana. Despite its weakening, Isaac continued to produce strong thunderstorms to the east and southwest of the center. Around 2100 UTC (4:00 p.m. CDT) on August 30, Isaac degenerated into a tropical depression over northern Louisiana.
The Hydrometeorological Prediction Center took over the responsibility on issuing advisories from the NHC at 0300 UTC on August 31. The depression continued generally northeastward over Arkansas and Missouri before transitioning into an extratropical cyclone on September 1 as it interacted with an upper-level trough. The remnants of Isaac continued generally eastward over southern Illinois before moving southward over Kentucky. On September 3, the mid-level circulation of the storm split into two parts, with one portion continuing southward into the Gulf of Mexico and the other eastward over Ohio.

Preparations

Lesser Antilles

Upon the issuance of the National Hurricane Center's first advisory for Tropical Depression Nine early on August 21, numerous islands across the Lesser Antilles were placed under hurricane watches or tropical storm warnings. By the end of the day, tropical storm warnings were in place for was issued for Anguilla, Antigua, Barbuda, the British Virgin Islands, Culebra, Dominica, Guadeloupe, Desirade, Les Saintes, Marie Galante, Martinique, Montserrat, Nevis, Puerto Rico, Saba, St. Eustatius, St. Maarten, St. Martin, St. Kitts, United States Virgin Islands, and Vieques. Hurricanes watches were also in place for Puerto Rico, Vieques, Culebra, and the United States Virgin Islands. As the storm continued westward towards the region, a hurricane watch was issued for the British Virgin Islands on August 22. Later that day, Isaac entered the eastern Caribbean Sea as a minimal tropical storm rather than a hurricane, resulting in the discontinuation of all previously issued hurricane watches. As the storm gradually moved further westward into the Caribbean, warnings were discontinued for the various islands, with all warnings ceasing by the end of August 23.

Greater Antilles and The Bahamas

At 0900 UTC on August 22, the government of the Dominican Republic issued a tropical storm watch along the north coast of the Dominican Republic, from the border with Haiti eastward to Saona Island. Simultaneously, a hurricane watch was put into place on the south coast, also extending from the Haitian border to Saona Island. At Guantanamo Bay Naval Base, a trial for five prisoners, who allegedly planned the September 11 attacks, was postponed.

At 1030 UTC on August 24, the government of Jamaica issued a tropical storm watch for the entire island of Jamaica. Early on the following day, the Cayman Islands Meteorological Service designated the Cayman Islands under a tropical storm watch. Several hours later on August 25, the tropical storm watches for both Jamaica and the Cayman Islands were discontinued.

Gulf of Mexico

Oil production in the Gulf of Mexico was down by 24% percent and gas off by 8%, as several major companies (including BP and Shell) evacuated their installations in the east part of the basin. Overall, at least 39 (7%) of 596 production platforms and eight (11%) of 76 Gulf oil rigs were evacuated in the Gulf on August 26. By the evening of August 27, approximately 78% of the Gulf's crude oil production and 48% of its natural gas production had been closed.

United States

Florida

At 2100 UTC on August 24, a tropical storm watch was issued for all of Florida south of the Jupiter Inlet on the east coast and south of Bonita Springs; it also included Lake Okeechobee and the Florida Keys. Early on the next day, the tropical storm watch was upgraded to a warning, while the Florida Keys and the mainland from Ocean Reef to Bonita Springs were now under a hurricane watch. Further north, a tropical storm watch was issued from the Jupiter Inlet to the Sebastian Inlet. Later on August 25, the hurricane watch was switched to a warning, while a separate hurricane watch was issued from Golden Beach southward.

During the week of August 27, the 2012 Republican National Convention was held in Tampa, Florida. Isaac threatened to force the cancellation or postponement of the convention; there was also potential to move the event's location. According to the Republican National Convention spokesman James Davis, officials had been coordinating with the United States Secret Service, should the 50,000 politicians, delegates, and reporters require evacuation. The Republican National Convention was pushed to August 28, with the storms threatening the coast of Tampa. Chairman of the Republican National Convention Reince Priebus announced on August 25 that the convention would only convene for a short amount of time on August 27 and "immediately recess until Tuesday afternoon, August 28". At the same time, Governor of Florida Rick Scott announced he would not be attending the convention, together with Governor of Alabama Robert J. Bentley. On August 25, Governor Scott declared a state of emergency for the state of Florida ahead of Tropical Storm Isaac. Amtrak suspended the ''Silver Meteor'' and ''Silver Star'' train service from Orlando to Miami on Sunday, August 26. In Miami-Dade County, evacuations were ordered for residents living in mobile homes. Additionally, the bridges across the Port of Miami were closed during the height of Isaac. Orange juice prices increased due to the threat of the storm in Florida, which produces more than 75 percent of orange crops in the United States.

The Florida Division of Emergency Management was put into partial activation, and Florida Power & Light brought in at least 4,300 workers to help with expected power outages. Key West International Airport suspended all flights in preparation of Isaac, while all cruises and many theme parks were delayed. The United States Coast Guard activated hurricane condition "whiskey", restricting the transportation of watercraft until the storm passed. In South Florida, specifically in Monroe County, many schools were used as shelters. In Miami-Dade County, all public schools and universities – including Florida International University and the University of Miami – cancelled classes. While the airport in the county remained open, it cancelled hundreds of flights and delayed many others. As the storm passed, regular services became available once again. Across the remainder of the state, especially in coastal counties, most schools and government buildings were closed. In Escambia County, a mandatory evacuation was ordered for zones A, B, and C. Many shelters were opened for those who had nowhere to go, and all county schools were shut down. At Naval Air Station Pensacola, many planes were either evacuated from the base or placed into secure hangars. Farther east in Santa Rosa County, a mandatory evacuation was also ordered for zones A, B, and C, including all mobile home parks, campgrounds, low-lying areas, and RV parks. In Walton County, special needs and general shelters were opened to the public, and all schools and government offices were to be shut down throughout the duration of the storm. The Clyde B. Wells Bridge was also shut down in anticipation of tropical storm-force winds.

Louisiana

Upon the issuing of hurricane watches warnings, Louisiana Governor Bobby Jindal declared a state of emergency for the entirety Louisiana, recommending evacuation of areas unprotected by levees or areas south of the Intracoastal Waterway. Mayor of New Orleans Mitch Landrieu took the same course of action for his city. However, he stated that the Louis Armstrong New Orleans International Airport, convention center, and Mercedes-Benz Superdome would not be emergency shelters. Residents of Plaquemines Parish's eastern bank were ordered a mandatory evacuation on August 26, while a voluntary evacuation was ordered for southern areas of the parish from Ironton to Venice. In other regions of the parish, levees were lined with visqueen to protect exposed dirt, with sandbags being added to levees in other locations including Pointe à la Hache. Evacuation orders were also placed for visitors and tourists in Grand Isle on the same day, with residents ordered to evacuate on August 27. In St. Charles Parish and Terrebonne Parish, 73,000 residents were ordered to evacuate. FEMA began to deliver meals and tarpaulins to the state on August 28. 4,000 National Guard troops were activated in the state. The closure of all schools and Universities in South East Louisiana, including Louisiana State University followed Gov. Jindal's State of Emergency declaration.

Governor Jindal announced that he would not attend the 2012 Republican National Convention and would remain in his state to take care of storm-related problems. On August 27, President Obama ordered federal aid to Louisiana to supplement state and local response efforts due to the emergency conditions resulting from Tropical Storm Isaac beginning on August 26, 2012. Governor Jindal on August 27 sent a letter to the Obama administration that the declaration fell short of the help he was requesting. Gov. Jindal had temporarily suspended Louisiana's licensing requirements for emergency medical technicians, to let medical assistance officials from other states help Louisiana respond to Hurricane Isaac. Louisiana Commissioner of Administration Paul Rainwater announced that all state government offices would be closed August 29. The US Army Corps of Engineers closed the Seabrook Floodgate and the IHNC Lake Borgne Surge Barrier to protect the New Orleans area from a storm surge.

Mississippi

Mississippi Governor Phil Bryant declared a state of emergency the evening of August 26, 2012 The governor ordered mandatory evacuations to begin at 8 a.m. CT (9 a.m. ET) on August 27 for residents along the coast and in some low-lying areas inland. On August 27, the Jackson County Board of Supervisors ordered a mandatory evacuation of all areas south of U.S. Route 90. It included all areas south of US 90 in Ocean Springs, Mississippi, Gautier, Mississippi and Pascagoula, Mississippi. The evacuation was in effect as of 4pm CT.
Officials dispatched 1,500 National Guard troops to the state's three southern counties, as well as 45 state troopers to ease traffic flow.
On August 28, the president signed an emergency declaration for the state of Mississippi.

Alabama

Alabama Governor Robert J. Bentley declared a state of emergency ahead of Isaac. Mandatory evacuations for Baldwin and Mobile counties beginning at 8:00 a.m. on August 27 for zones one and two. Governor Bentley soon announced that he would not be attending the 2012 Republican National Convention, and will remain in his state to take care of storm-related problems.
On August 28, Governor Bentley lifted the mandatory evacuation orders covering southern Baldwin and Mobile counties and issued voluntary orders for areas vulnerable to Isaac's expected impact.

Impact and aftermath

Lesser Antilles

In Martinique, a meteorologist reported at least of rain.

Venezuela

Isaac did not directly impact Venezuela, but the storm's outer bands produced heavy rains over part of the country. In the state of Sucre, the Manzanares River overflowed its banks in the town of Cumanacoa, flooding approximately 1,200 homes, many of which were damaged and a few destroyed. Some residents had to be airlifted to safety. Similar flooding occurred elsewhere in the country, such as in Caracas where 40 families had to be evacuated. Across Caracas, transportation was significantly disrupted as the local Metro suspended service and debris blocked local roads. The most significant flooding in the city occurred in western areas where hundreds of families had to be evacuated. In the state of Monagas, heavy rains and high winds damaged a total of 47 homes. Several roads were blocked by downed trees and flooding, temporarily isolating a few cities. Across the states of Anzoátegui, Monagas, and Sucre, 3,200 families were affected by the floods and 600 homes were damaged or destroyed. In the state of Yaracuy, flooding destroyed 10 homes and affected 70 others. At least two people were killed and two others were listed as missing in various events related to the storm.

Greater Antilles

Authorities estimated at least 30,000 residents were evacuated across the island of Hispaniola.

Haiti

Isaac swept across Haiti's southern peninsula, bringing flooding and storms in areas affected by the January 2010 earthquake. A woman and a child died in the town of Souvenance, and a 10-year-old girl died in Thomazeau when a wall fell on her. A seven-year-old boy was electrocuted in the city of Gonaives. As many as 5,000 people were evacuated because of flooding, as scores of tents in quake settlement camps collapsed and at least 300 houses were flooded in the Port-au-Prince shantytown of Cité Soleil. Doctors Without Borders announced it anticipated a spike in cholera cases due to flooding and it was preparing to receive more patients. President Michel Martelly canceled his trip to Japan to coordinate emergency response efforts and visit residents with Prime Minister Laurent Lamothe. On August 26, 2012, the Haitian government announced that at least 14,000 people had left their homes, while another 13,500 were living in emergency shelters. According to official figures, at least a dozen houses were destroyed and 269 damaged during the storm. On August 28, the death toll in Haiti was revised up to at least 24, with three others missing. News reports in the area stated up to 29 deaths, however.

Agricultural losses across the country amounted to $242 million. Damage to the nation's electrical infrastructure reached 336 million gourdes (US$7.9 million).

Dominican Republic

Authorities in the Dominican Republic evacuated nearly 7,800 people from low-lying areas, and at least 10 rural settlements were cut off by flooding. Parts of Santo Domingo lost electricity during the height of the storm. At least five fatalities were reported, including three men who drowned in flooded rivers, and 49 homes were destroyed throughout the country. Agricultural losses across the country were estimated to be at least $30 million.

Cuba

The center of the storm crossed Cuba west of Maisí, the extreme eastern tip of Cuba, according to state television. In Baracoa, the electricity was cut off as a preventive measure, and at least two houses were destroyed by flooding. Authorities announced 230 people were in emergency shelters. Intermittent rains and gusty winds were present even in Havana

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