Frederic IR Satellite (source NOAA)

 

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 Frederic formed on August 29 as a tropical depression over the far eastern Atlantic and became a hurricane on September 10 over the Gulf of Mexico.

Frederic strengthened to a Category 4 hurricane over the Central Gulf with maximum sustained winds near 132 mph.


Frederic Track History (source NOAA)


On Wednesday, September 12, 1979 at 5am CDT, the National Weather Service issued Hurricane Warnings from Panama City, FL west to Grand Isle, LA. Frederic continued to strengthen with highest winds estimated at 130 mph and central pressure of 28.05 inches of mercury. Frederic continued moving northwest with a slightly increased forward speed at 12 mph located about 220 miles south of the Alabama Coast. Hurricane Frederic was expected to produce a storm surge of 10 to 15 feet above normal in the area where the center made landfall.

By 11am on September 12th, Frederic was located 175 miles south of Pensacola moving north-northwest at 12 to 15 mph. The diameter of the hurricane eye was reported to be about 10 miles. Reports from hurricane hunter reconnaisance aircraft and coastal weather radar networks indicated the eye of Frederic would cross the coast between Gulfport, MS and Pensacola, FL. Evacuation of the Gulf Coast was nearing completion at that time.

By 5pm on September 12th, the center of Hurricane Frederic was approximately 80 miles south of Gulf Shores, AL moving north at 15 mph.


Frederic IR Satellite (source NOAA)Frederic IR Satellite Image (source NOAA)

Conditions began to rapidly deteriorate during the afternoon of September 12th as Frederic approached the Alabama Gulf Coast. Hurricane Frederic approached the coast with a forward speed of 15 mph. The eye of the Frederic measured 50 miles in diameter east to west and 40 miles north to south. In the opinion of some weather forecasters at the time, Frederic had the largest storm center they had ever recorded.

Shortly before 10pm on September 12th, the northern eyewall of Frederic move ashore on Dauphin Island, AL. As the eye moved inland, it decreased in size to about 15 miles in diameter. The storm center crossed over the western end of Dauphin Island at 10pm. An automated wind gust recorder (located at the top of the Dauphin Island Bridge), recorded a peak wind gust of 145 mph around 940pm. At landfall, Frederic was as strong Category 3 on the Saffir Simpson Hurricane Intensity Scale,raking the Mobile Bay area with winds gusting from 100 to 145 mph for several hours on the evening of September 12th through the early morning of September 13th. Hurricane wind gusts were experienced as far inland as Choctaw County, AL during the early morning hours of September 13th.


Frederic Storm Surge Damage Gulf ShoresStorm Surge Damage Alabama Coast Frederic

The damage cost from Frederic was $2.3 billion. Five deaths were directly attributable to the storm. A storm surge of 12 to 15 feet on the Gulf beaches and 8 to 10 feet in northern Mobile Bay destroyed numerous coastal buildings. Storm surge damage was documented for 80 miles along the coast.


Dauphin Island surge and overwash damage

The winds from Hurricane Frederic damaged or destroyed many homes and businesses. Many homes and businesses well inland suffered severe damage when large pine trees fell onto them or the roof structures failed. Along with peak wind gusts of 145 mph at the Dauphin Island Bridge, wind gusts of 97 mph from the east were recorded at Mobile Regional Airport at 1107pm. At midnight, Mobile County Civil Defense also reported measured wind gusts at 97 mph, along with massive damage in Mobile and surrounding areas. At midnight, wind gusts from the north at 98 mph were reported by Biloxi Civil Defense with north winds gusting to 127 mph at Ingalls Shipbuilding in Pascagoula, MS.


Fujita Wind Damage Analysis

At 2am on Thursday, September 13th, the National Weather Service issued an intermediate advisory reporting the center of Hurricane Frederic had passed just west of Mobile and the hurricane force winds began to slowly subside in the Mobile area as Frederic continued to move north along the Alabama/Mississippi border. Extensive reports of damage in the Mobile metropolitan area were beginning to come in to the NWS. After moving inland from the coast, the hurricane moved north and then northeast, increasing its forward speed to 23 mph. It did not lose hurricane intensity until it was in the vicinity of Meridian, MS at about 7am.

By 8am on September 13th, Frederic was downgraded to a tropical storm. Frederic maintained that intensity as it moved north through Mississippi, crossing back into Alabama west of Tuscaloosa. Late that afternoon, Frederic was further downgraded to a tropical depression as it moved north through Alabama.


Downtown Mobile Roof FailuresLong Leaf Pine Damage Mobile County

Numerous large swaths of significant wind damage were documented in the days immediately following the landfall of Frederic. Fallen trees were a significant impact to residents, bringing down thousands of power lines and blocking roads for several days. Some areas of Mobile County experienced electric power outages for 5 weeks.


Frederic Rainfall Image

Frederic moved north along the Alabama/Mississippi border dropping 3 to 11 inches of rain along its path. The highest rainfall total of 11 inches was reported in Pascagoula, MS.


Dauphin Island Sea Lab Pressure Trace
      Microbaragraph trace from Dauphin Island Sea Lab (NOAA)

The lowest barometric pressure recorded in Frederic by NOAA Hurricane Hunter reconnaisance aircraft was 943 mb or 27.85 inches of mercury. Mobile Regional Airport set an all-time recorded low barometric pressure at 1040pm on September 12th, 1979 of 28.38 inches of mercury. Dauphin Island Sea Lab reported a minumum pressure of 943 mb or 27.85 inches of mercury.

Over 500,000 people evacuated from the Central Gulf Coast Region ahead of Hurricane Frederic - the largest evacuation along the Gulf Coast up to that time. Frederic was the first hurricane to directly strike Mobile since 1932. Before Frederic, the last hurricane with Category 3 winds to directly strike the Alabama Gulf Coast occurred in 1916. There was also the 1926 “Great Miami” Hurricane that weakened to a Category 2 storm as it passed over Fort Morgan and Dauphin Island, AL.

 

Additional Information:

Visible Satellite Loop (August 30th through September 13th)

Radar Loop (September 10th through September 14th)

Weather Prediction Center (WPC) Rainfall Maps

Hurricane Reaseach Division (HRD) Aircraft Missions into Frederic

 


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