Tracks of the 50 mesocyclones and multiple tornado vortex signatures (denoted by inverted red triangles) identified by the NWS Office in Tallahassee, Florida between 1:00 p.m. on September 15 to 9:00 a.m. on September 16.
Type
Tornado outbreak
Duration
September 15–18, 2004
Tornadoes confirmed
120[nb 1] (Record for a continuous outbreak in September)
1Most severe tornado damage; see Fujita scale 2Time from first tornado to last tornado
The Hurricane Ivan tornado outbreak was a three-day tornado outbreak that was associated with the passage of Hurricane Ivan across the Southern United States starting on September 15, 2004, across the Gulf Coast states of Alabama and Florida as well as southern Georgia before ending in the Middle Atlantic Coast on September 18.
The outbreak killed 7 people and injured dozens of others across several states from Florida to Pennsylvania. The hurricane itself killed at least 90 people from the US to the eastern Caribbean Islands. Overall, it produced 120 tornadoes, surpassing the record of 117 that was previously held by Hurricane Beulah during the 1967 Atlantic hurricane season.[4] Ivan also produced 16 more tornadoes than Hurricane Frances, whose associated tornado outbreak struck many of the same regions about ten days earlier. The tornado outbreak was also the largest in Virginia history.[5]
On September 13, 2004, as Category 5 hurricane Ivan moved through the Yucatán Channel,[6] the Storm Prediction Center noted the possibility of isolated tornadoes for parts of Louisiana and the Florida Panhandle three days out.[7] Though the storm weakened while approaching the United States, strong low-level wind shear along its northeastern periphery allowed for the development of potentially tornadic supercells.[8] A National Oceanic and Atmospheric AdministrationHurricane Hunter aircraft intercepted Ivan during the afternoon and evening of September 15. During the mission, dropwindsondes were deployed off the Gulf Coast to assess the rainband environment. By this time, an intense band of thunderstorms, with embedded supercells, developed about 250 mi (400 km) east of the hurricane's center. A thermodynamic sounding around 1:00 p.m. EST from Tampa Bay, Florida revealed unusually favorable conditions for deep, rotating convection. Ahead of the band, convective available potential energy (CAPE) levels reached 2,500 J/kg and significant helicity.[9] The significant levels of CAPE, accompanied by a dry air intrusion between the rainband and the main convection of Ivan, were the primary cause of the outbreak. A comparison between Ivan and Hurricane Jeanne revealed that both storms encountered similar conditions near landfall; however, CAPE values were lower during Jeanne and the system produced far fewer tornadoes.[10]
In light of the increased tornado threat, the first tornado watch was issued around 1:00 p.m. EST for the Florida Panhandle and southern Alabama.[11] By then, "miniature" supercell thunderstorms began approaching the coastline. Data from Doppler weather radar indicated mesocyclones within several of the cells, though mostly while over water. At the onset of the outbreak, three cells exhibited signature characteristics of supercell thunderstorms: cyclonic updraft and a hook-like appendage. Similar to storms over the Great Plains, a mid-level rear flank downdraft was present; however, this feature did not reach the surface.[9] Less than an hour after the watch was issued, the first tornado of the outbreak touched down in Escambia County, Florida. Over the course of the next 20 hours, the National Weather Service (NWS) office in Tallahassee monitored over 50 mesocyclones that had sufficient vorticity to spawn tornadoes. The high number of potential storms led to the issuance of 130 tornado warnings, of which only 20 later verified. One of the mesocyclones had a "nearly textbook appearance" and produced four tornadoes between 8:15 p.m. and 9:50 p.m. as it traveled nearly 75 miles across the Florida Big Bend.[1][2] Two of these tornadoes reached F2 intensity and, collectively, they killed four people, injured eight more, and left $5.5 million in damage. By midnight on September 15, 26 tornadoes had touched down across three states.[1]
With the tornado threat gradually moving northward, new tornado watches were issued further north into much of South Carolina.[12] During the first half of September 16, several F0 tornadoes touched down across the Southeast.[1] By the afternoon, downstream subsidence limited thunderstorm activity; however, as the day wore on, sufficient warm, moist air from the Gulf Stream and breaks in cloud cover allowed for CAPE values to rise.[13] Extensive convective banding to the north and east of the storm continued to encounter extreme levels of helicity. Subsequently, numerous rotating thunderstorms developed over the region, especially across Georgia and South Carolina.[14] Throughout the afternoon, 22 tornadoes touched down across the two states, one of which, an F2, killed one person.[1] The majority of the activity took place along a warm front that developed east of Tropical Storm Ivan within the shear maxima.[15]
Following a lull in activity during the overnight hours between September 16 and 17, conditions once more became increasingly favorable for tornadoes across North Carolina and Virginia. Strong shear associated with the weakening tropical cyclone and the destabilization of air ahead of the main rainband and consequently, a tornado watch was issued for portions of both states around 10:00 a.m.[16]
The tornado outbreak began during the early afternoon of September 15, when the first outer rain bands and thunderstorms moved ashore across the southern states. One person was killed in Panama City, Florida when a tornado tore through the city damaging many businesses. The tornado that hit just before 4:00 p.m. was caught on camera as it skirted just outside a local television station that was doing severe weather coverage as tornado warnings were issued in the Panama City media market area.[17] At the same time, another deadly tornado touched down in Bay County, Florida killing 1 when a wood-frame home was lifted and smashed, killing an occupant.[18] Later during the evening many other tornadoes touched down across the Panhandle region of west Florida. An F2 tornado in Calhoun County, Florida tossed mobile homes in the air, killing two occupants in each of 2 mobile homes.[19] At the same time the center of the hurricane was approaching the Florida/southern Alabama state and coastline near Gulf Shores. At least 26 tornadoes were confirmed during the day.
After the cyclone made landfall near Gulf Shores, Alabama, the tornado activity shifted further north into central Alabama and the northern half of Georgia as well as South Carolina. One person was killed in Franklin County, Georgia by an F2 tornado that damaged several businesses and homes. 32 tornadoes were confirmed on that day.[20] As the remnants of Ivan, now a tropical depression moved further inland, increased instability and thunderstorm cells produced a large tornado outbreak from the northern Carolinas to Pennsylvania. Virginia was the hardest hit state during the day as nearly 40 tornadoes affected the state.[21] Several F2s and one F3 touched down, causing significant damage to numerous structures including homes and businesses. Areas roughly to the west and south of Washington, D.C. were the hardest hit areas. Nearly 60 tornadoes were confirmed on that day before the outbreak ceased during the overnight hours of September 18 across Maryland.
1 death – A strong F1 tornado touched down near the St. Andrews recreation area, where it damaged dozens of commercial structures. Traveling northward, the storm then moved through Grand Lagoon. There, one person was killed when a real estate office was destroyed and seven others were injured in a restaurant. The tornado came within 100 yards (91 m) of the WJHG-TV station before dissipating. Overall, damage from this event was estimated at $5 million.[27]
1 death – Shortly after the previous tornado touched down, another formed near Allanton. This storm lofted a wood-frame home, with seven people inside, about 60 feet (18 m) into a field; one person was killed and another was injured. Several other homes were damaged before the tornado dissipated.[29]
Another F1 tornado touched down in Bay County, this time near Cedar Grove, and destroyed several homes along its path. Losses from the storm reached $2 million.[31]
A relatively long-lived tornado damaged five homes and several chicken houses in Whigham. Numerous trees and power lines were also felled by the storm, blocking off many roads.[35]
4 deaths – A strong F2 tornado touched down near Blountstown and tracked northwestward. After crossing Highway 69, it damaged dozens of homes and uprooted trees. Shortly thereafter, it moved through the Macedonia Community where three trailers were destroyed and 30 homes damaged. Within the community, four people were killed and five others were injured after their mobile homes were thrown into other structures. The tornado subsequently dissipated near Altha. Overall losses from the event reached $2.5 million.[46]
The final Florida tornado on September 15 touched down east of Marianna and struck the Gold Drive Trailer Park. There, it destroyed 25 mobile homes and damaged 10 more. Three people sustained injuries in Gold Drive. Tracking northwest, the storm moved through the Brogdon Lane Trailer Park and damaged 10 more mobile homes and subsequently caused significant damage to the Marianna Federal Correctional Institution. The tornado then destroyed the Sykes Enterprises facility near Marianna Municipal Airport before dissipating. Overall losses from the storm reached $3 million.[49]
September 16 event
List of reported tornadoes – Thursday, September 16, 2004
A weak tornado touched down near Lake Miccosukee and tracked northeast, damaging two homes and destroying a shed. Numerous trees and power lines were felled by the storm.[56][57]
A weak tornado damaged several homes and felled many trees. A portion of Georgia State Route 133 near Pecan City was temporarily closed due to downed trees.[59]
An F1 tornado touched down near Georgia State Route 72 and tracked north-northwest towards a country club. There, five large homes sustained extensive damage. Twenty other homes were also damaged by the tornado before it dissipated near the Madison County High School in Danielsville. Overall losses from the storm reached $1.3 million.[61]
Strong tornado struck the town of Franklin Springs, damaging or destroying 25 residential structures. Additionally, the local fire and police stations sustained damage. Overall losses from the storm reached $1.1 million.[64]
Brief tornado touched down near the Griffin-Spalding Airport. Several large trees were significantly damaged and many others were uprooted. A few homes sustained minor roof damage.[66]
Relatively large tornado, measured up to 500 yd (460 m) wide, caused significant damage in Tignall and Norman. A total of 23 structures were damaged along the storm's path to varying degrees. Numerous trees and power lines were downed, twisted, or uprooted. Additionally, a large communications tower was destroyed. Overall losses from the storm reached $1.5 million.[67]
Tornado touched down near Fortsonia and damaged a house. One person inside the house sustained injuries. Damage along the remainder of the path was confined to trees.[68]
1 death – Strong tornado touched down west of Franklin Springs and damaged many buildings, vehicles, and trees. One person was killed after her car was hit by a fallen tree. A passenger in the car was also injured.[70]
Brief tornado downed dozens of trees, many of which fell on homes and vehicles, resulting in four injuries. Six homes were damaged by the downed trees and losses from the storm reached $300,000.[71]
Tornado tracked through Stokesdale and caused widespread damage. Three homes were destroyed, nine were severely damaged and fifty-two others were affected. Seventy percent of the trees in a heavily wooded area near the town were snapped or uprooted.[84] Continuing into Rockingham County, the tornado damaged several more homes and destroyed a double-wide trailer before dissipating.[85]
40 vehicles were damaged or destroyed at a factory which sustained significant damage. There was roof and tree damage at a subdivision. A residential garage was damaged by a fallen tree, and two semi-trucks were overturned. 4 people were injured.
Several homes in a subdivision had their roofs torn off, and one home was shifted from its foundation. Garages and outbuildings were destroyed, and large trees were snapped and uprooted. Maximum structural damage was F2, as the F3 rating was based on a car that was lofted more than 75 yards over trees and power lines. Two people were injured.
A cinder-block detached garage was destroyed, and a mobile home was destroyed by a falling tree. Two vehicles were damaged and trees were snapped. Several homes sustained minor damage.
A detached parking garage was destroyed, while three homes sustained roof damage and. A platform deck was blown away and an office trailer was overturned. Numerous trees were snapped and uprooted and outbuildings where damaged.
Tornado snapped or uprooted many large hardwood trees. Some of the trees fell on houses and other structures. A vehicle was moved several feet, and homes sustained roof damage.
In Frederick County, the tornado destroyed outbuildings and other structures. Other buildings sustained roof damage and trees were downed. In Washington County, the tornado downed more trees, some of which landed on homes.
A short-lived tornado downed several trees and peeled the siding off a few homes. One of the trees fell on a home, causing extensive roof damage and breaking most of the windows.[86]
^Stacy R. Stewart (May 16, 2005). "Tropical Cyclone Report: Hurricane Ivan"(PDF). National Hurricane Center. National Oceanic and Atmospheric Administration. Retrieved May 22, 2015.
^Jeffry S. Evans (September 15, 2004). "Tornado Watch 823". Storm Prediction Center. National Oceanic and Atmospheric Administration. Retrieved November 3, 2011.
^Greg L. Dial; Jeffry S. Evans (September 16, 2004). "Tornado Watch 830". Storm Prediction Center. National Oceanic and Atmospheric Administration. Retrieved November 10, 2011.
^Greg L. Dial (September 16, 2004). "Mesoscale Discussion 2225". Storm Prediction Center. National Oceanic and Atmospheric Administration. Retrieved November 10, 2011.
^Gregory Carbin (September 16, 2004). "Mesoscale Discussion 2221". Storm Prediction Center. National Oceanic and Atmospheric Administration. Retrieved November 6, 2011.
^Jonathan Racy (September 16, 2004). "Mesoscale Discussion 2227". Storm Prediction Center. National Oceanic and Atmospheric Administration. Retrieved November 10, 2011.
^Jeffry S. Evans (September 17, 2004). "Tornado Watch 832". Storm Prediction Center. National Oceanic and Atmospheric Administration. Retrieved November 12, 2011.
^National Weather Service Office in Mobile, Alabama (2004). Florida Event Report: F0 Tornado (Report). National Climatic Data Center. Retrieved May 23, 2014.
^National Weather Service Office in Mobile, Alabama (2004). Alabama Event Report: F0 Tornado (Report). National Climatic Data Center. Retrieved May 23, 2014.
^National Weather Service Office in Mobile, Alabama (2004). Florida Event Report: F0 Tornado (Report). National Climatic Data Center. Retrieved March 6, 2016.
^National Weather Service Office in Mobile, Alabama (2004). Florida Event Report: F0 Tornado (Report). National Climatic Data Center. Retrieved March 6, 2016.
^National Weather Service Office in Tallahassee, Florida (2004). Florida Event Report: F0 Tornado (Report). National Climatic Data Center. Retrieved March 6, 2016.
