Figure 1. Best Track analysis of Hurricane Ivan—a long-lived Cape Verde hurricane.1
Light Red=Category 1-2 Hurricane
Dark Red=Category 3-5 Hurricane
When Ivan finally dissipated over extreme eastern Texas, he had completed a path that measured more than 5600 miles in length.2 Furthermore, Ivan’s ACE index (Accumulated Cyclone Energy) was 70.4 104kt2, which remains one of the highest in Atlantic Hurricane history. The ACE index was developed by the National Oceanic and Atmospheric Administration as a way to measure the amount of wind energy expended by a given tropical cyclone. ACE is defined by summing the squares of the maximum velocity of the wind of a Tropical Storm at six-hour intervals (Vmax), over a constant (104 knots).3
Ivan formed in the deep tropics just west of the Cape Verde Islands from a strong tropical wave that raced off the African coast between the 30 and 31 August A surface low quickly developed over the extreme eastern Atlantic (See Figure 2), but convection remained too disorganized for the system to be classified as a Tropical Depression.
Figure 2. Surface Analysis at 12Z 20 August, 2004. The Low pressure system noted just west of Africa will eventually become Hurricane Ivan.4
The wave became Tropical Depression Nine about 560 miles southwest of the Cape Verde Islands on 2 September as it moved westward at a fairly good clip of 20 mph.5 Early the next morning, satellite images indicated that the Depression had strengthened into Tropical Storm Ivan, even though he was situated under modest easterly wind shear, which was blowing thunderstorm activity away from the storm’s center of circulation.
Nevertheless, Ivan continued to strengthen—slowly at first—traversing the very warm waters of the southern Atlantic, before developing into the sixth hurricane of the 2004 Atlantic Hurricane Season at around 5 AM EDT on 5 September.6 This signaled the beginning of a much quicker intensification phase, and Ivan became a very powerful Category 4 Hurricane a short 18 hours after classification as a Category 1. On top of the rapid intensification, Ivan had become the most southerly major hurricane (Category 3 or greater) ever at 10.6 degrees latitude.
Ivan maintained major hurricane status for another 12 hours, before weakening to a 90 kt (105 mph) Category 2 during the afternoon on 6 September as he approached the southern Lesser Antilles. This low point in Ivan’s intensity was short-lived, however, as he regained Category 3 status the next morning while clipping the Islands of Tobago and Barbados at the southern end of the long island chain that makes up the Lesser Antilles. After passing through the Antilles, Ivan veered slightly north, paralleling the north coast of South America. Idyllic conditions existed throughout the entire Caribbean Sea, and Ivan took advantage of everything, rapidly deepening into a 140 kt (160 mph) Category 5 Hurricane on the Saffir-Simpson Hurricane Scale on 9 September. Ivan briefly lost Category 5 status while passing just south of Jamaica, lashing the island with winds upwards of 120 kts (140 mph).
Ivan began to turn to the northwest and then re-strengthened into a Category 5 for the second time on 11 September before once again weakening slightly while approaching the Yucatan Peninsula. Ivan re-gained Category 5 status for the third and final time while passing through the Yucatan Channel on 14 September. Luckily, Ivan weakened—albeit slowly—before its first US landfall near Gulf Shores, Alabama at 4 AM CDT on 16 September (See figure 3).7
Figure 3. Hurricane Ivan making landfall near Gulf Shores, Alabama during the early morning of 16 September, 2004. Image Courtesy of the National Weather Service Mobile, Alabama
Ivan weakened over land, and became a Tropical Depression on 17 September over northern Alabama. Ivan re-generated into a Tropical Depression on 22 September, and proceeded to complete a large, anti-cyclonic loop around the Southeast states later that day. Ivan briefly intensified to a minimal Tropical Storm before making his final landfall near Cameron, Louisiana on 23 September as a Tropical Depression.8
Data, Images and Animations
+Explore and analyze gridded data of the hurricane using the GES-DISC Interactive Online Visualization and Analysis Infrastructure (Giovanni)
+Use Mirador or WHOM to obtain data provided by the GES DISC DAAC for a hurricane event.
+View animations and images of Hurricane Ivan in the 2004 Past Hurricane Archive.
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MODIS Terra RGB using the MOD02HKM product. This image is of the swath data from Sept 14 at 1640 hrs. More images like this and parameters animation created from other datasets can be seen in our Archive Image Gallery for hurricane Ivan
1. Image courtesy of the NOAA coastal Services Center Http://hurricane.csc.noaa.gov/hurricanes
2. Stewart, Stacy. “Tropical Cyclone Analysis: Hurricane Ivan.” 16 December 2004. http://www.nhc.noaa.gov/2004ivan.shtml (26 July 2006).
3. Bell, Gerald D, et al. “Climate Assessment for 1999.” Journal of the American Meteorological Society. 81.6 (2000): 19-20.
4. Image courtesy of Chris Burr at the National Hurricane Center
5. Knabb, Richard; Pasch, Richard. “Tropical Depression Nine Advisory Number 1.” 2 September 2004. http://www.nhc.noaa.gov/archive/2004/pub/al092004.public.001.shtml? (26 July 2006).
6. Beven, Jack. “Hurricane Ivan Discussion Number 11.” 5 September 2004. http://www.nhc.noaa.gov/archive/2004/dis/al092004.discus.011.shtml? (26 July 2006).
7. Avila, Lixion. “Hurricane Ivan Advisory Number 56.” 16 September 2004.” http://www.nhc.noaa.gov/archive/2004/pub/al092004.public.056.shtml? (27 July 2006).
8. Avila, Lixion. “Tropical Depression Ivan Intermediate Discussion Number 71A.” 23 September 2004. http://www.nhc.noaa.gov/archive/2004/pub/al092004.public_a.071.shtml? (27 July 2006).