Damage estimates vary from $4-8 billion (2005 USD), with variations due to inadequate reporting of private insurance claims as well as lack of hard data on uninsured damage. FEMA, which had been established only three months before Frederic hit, was the focal point for nearly $250 million in federal aid for recovery, $188 million of which went to Alabama (1979 USD).
Although conditions were initially very favorable for significant intensification, Frederic began to experience the outflow of Hurricane David (which had greatly intensified in the same area just days before). Subsequently, Frederic began a weakening trend early on September 2, when it weakened back to tropical storm status: this weakening trend would continue for several days as the storm followed in David's wake. Frederic passed over Puerto Rico and approached the Dominican Republic, then suddenly turned northwest during the afternoon of September 5 (just as David had done before): it passed just west of Santo Domingo on September 6. Further weakening caused Frederic to drop below tropical storm strength later on the 6th just north of Haiti.
Continuing westward, Frederic crossed southeastern Cuba before paralleling the island's southern coast for the next four days. During this period, Frederic eventually escaped the unfavorable conditions left behind by David and regained tropical storm strength 100 miles (160 km) east of Cuba's Isle of Pines at about 0000 (GMT) on September 9. A turn towards the northwest followed, and Frederic became a hurricane once more near 1200 (GMT) on September 10, as it moved away from the western tip of Cuba. Frederic achieved this despite its center of circulation remaining close to land, probably because of sea surface temperatures of 29-30C and favorable upper-level conditions due to the presence of a large anticyclone at 200mb over the storm.
Frederic continued to intensify as it moved into the Gulf Of Mexico, reaching peak intensity on 1200 (GMT) on September 12: at this time, Frederic had maximum sustained winds of 135 mph (215 km/h) and a central pressure of 943 mb (HPa), making a Category 4 hurricane.
Frederic weakened slightly before it made landfall on Dauphin Island, Alabama at 0300 (GMT) on September 13. Sustained winds were estimated at 125 mph, making Frederic a strong Category 3 hurricane at the time. The central pressure at the time was 946 mb. Landfall on the mainland occurred about an hour later near the Mississippi state line.
Moving inland, Frederic turned north and northeast and was downgraded to a tropical storm near Meridian, Mississippi. Frederic became extratropical in southwestern Pennsylvania as it merged with a frontal low in at about 1200 (GMT) on September 14, and moved rapidly northeastward before dissipating.
Sustained winds of 25-35kt with gusts up to 60kt buffeted the northeastern Caribbean. Frederic brought heavy rains to the Virgin Islands, where some tornadoes were also reported; in St. Thomas, 12 inches (0.3 m) of rain fell in the space of 24 hours, while 24 inches (.6 m) fell in the space of 30 hours in St. Croix. At St. Maarten, a fishing boat sank killing seven people.
As much as 10 inches (0.3 m) of rain falling in 12 hours was reported in the eastern part of Puerto Rico. There were also some reports of tornadoes.
Heavy rains of up to 24 inches (.6 m) in total were experienced in the Dominican Republic for several days after the center of Frederic's circulation passed, which worsened the damage caused by David just a week earlier.
Frederic had minimal impact in eastern Cuba, but damage estimates were high in western Cuba due to a strengthening Frederic bringing tropical storm-force winds and heavy rains.
Wind damage was also severe, especially across southern Alabama. Hurricane-force gusts were felt as far inland as Choctaw County. Structural failure was widespread in the immediate landfall area with industrial, residential and governmental buildings as well as hospitals suffering heavy damage. Nearly 90% of the Mobile area lost electricity, and the historic City Hall experienced heavy roof damage. Many small beach houses were completely destroyed by high winds before the storm surge could add any effects.
Tree damage with broken limbs was extensive, leaving thousands of tall pine trees all tilted, leaning in the direction the wind had come.
Frederic also dumped heavy rainfall across much of the eastern United States: 8 to 12 inches (.3 m) of rain fell from Pascagoula to Mobile, and 2-4 inches fell along the hurricane's path as far as New England. Over a dozen tornadoes were also reported in Frederic's wake. However, these had minimal impact.
Five deaths were directly attributed to Frederic in the United States, four of which occurred inland: a person swept from a boat near Pensacola was the only casualty along the coast.
In total, Frederic was responsible for $2.3 billion (1979 USD). This made Frederic the costliest hurricane in the history of the United States (until it was surpassed by Hurricane Hugo ten years later).
In retrospect, Frederic has been credited with spurring redevelopment in Mobile and the surrounding Gulf Coast region. For example, in testimony before Congress in 1992, Robert Sheets (then the director of the National Hurricane Center), described the economic aftermath of Frederic:
Asymmetric Distribution of Convection Associated with Tropical Cyclones Making Landfall along the South China Coast
Oct 01, 2004; ABSTRACT This study investigates the asymmetric distribution of convection associated with tropical cyclones making landfall...