2004 Atlantic hurricane season

A late start and an extraordinary peak

The archive's totals agree with the National Hurricane Center's season summary: fifteen named storms, nine of which became hurricanes and six of those major hurricanes, plus one tropical depression that never reached storm strength. The count includes Nicole, a short-lived subtropical storm near Bermuda, which is why its peak appears blank in the storm table even though it is part of the season total. The NHC compared these numbers with 1944 to 2003 means of about 10 named storms, 6 hurricanes and 2.6 major hurricanes, and measured the season's energy at 234 percent of the long-term average. Only 1950 and 1995 had produced more since 1944, and August and September 2004 together set a record for the most energy in any two-month span.

The ocean was primed. Waters between 10 and 20 degrees north in the tropical Atlantic and Caribbean were the second warmest since 1948 during the peak months, continuing a run of warm, active seasons that began in 1995, and wind shear over the Caribbean and western Atlantic was lower than normal. The unusual ingredient was the steering. For much of the previous decade a trough near the US East Coast had turned storms out to sea; in 2004 persistent high pressure over the eastern United States and western Atlantic kept storms on westward tracks toward the islands and the mainland, and the low shear let them keep much of their strength as they arrived. A mild El Niño developed during the summer, but its warmth sat far enough west in the Pacific that it did little to hold the Atlantic back.

Forecasters expected an above-normal year but not one this active. In May, NOAA called for 12 to 15 named storms, 6 to 8 hurricanes and 2 to 4 major hurricanes, and Colorado State University predicted 14, 8 and 3. The university team trimmed its outlook in early August, citing the mild El Niño, then raised it again in September as the season exploded.

Eight storms in August, then Ivan

June and July passed without a named storm. The first depression formed off the Southeast US coast on 31 July and became Tropical Storm Alex the next day, one of the latest starts in decades. Alex then set the tone: it brushed the North Carolina Outer Banks with its western eyewall on 3 August and, racing northeast over the open Atlantic, became a major hurricane at 105 kt near 38.5 degrees north; only one earlier hurricane had reached major strength farther north.

August went on to produce eight named storms, a record for the month. Bonnie crossed the Gulf of Mexico to the Florida Panhandle, Charley exploded into a Category 4 hurricane before hitting southwest Florida on 13 August, and Danielle and Earl formed from waves off Africa. At the end of the month, Frances was growing into a large Category 4 hurricane east of the Caribbean while Gaston and Hermine spun up close to the US East Coast from the same decaying front.

September belonged to the long-lived Cape Verde hurricanes. Ivan formed on 2 September and lasted into the fourth week of the month, Jeanne developed near Guadeloupe on 13 September, and Karl and Lisa followed in the central Atlantic. Karl became the sixth and last major hurricane on 19 September, and Lisa looped around a neighbouring disturbance before finally becoming a hurricane on 2 October, thirteen days after it formed. Activity then faded quickly. Tropical Storm Matthew and Subtropical Storm Nicole came and went in early October, and after a six-week lull Otto formed far east of Bermuda at the end of November, lingering until 3 December.

Ivan and the other major hurricanes

Hurricane Ivan was the season's strongest, lowest-pressure and longest-lived storm. It became the southernmost major hurricane on record, at 10.2 degrees north, less than three days after forming, and went on to reach Category 5 three separate times in the Caribbean. The archive records its peak of 145 kt on 11 September near the western tip of Jamaica, with a minimum pressure of 910 hPa early on 12 September, a reading the NHC measured again on 13 September and one bettered by only five earlier Atlantic storms. Ivan spent ten days as a major hurricane, a record since 1944, and eight straight days at Category 4 or stronger.

Three more storms reached Category 4. Hurricane Charley peaked at 130 kt and 941 hPa at the moment of its Florida landfall, after its pressure fell about 5 hPa an hour in the final hours of approach. Hurricane Frances reached 125 kt and 935 hPa north of the Leeward Islands at the end of August, and Hurricane Karl matched its 125 kt over the open central Atlantic on 21 September without threatening land. Hurricane Jeanne and Hurricane Alex each peaked at 105 kt, Category 3, while Hurricane Danielle fell just short of major status at 95 kt.

Florida's four hurricanes and the Caribbean toll

Five hurricanes, Charley, Frances, Gaston, Ivan and Jeanne, made landfall in the United States, and Bonnie, Hermine and Matthew came ashore as tropical storms. Florida took the heaviest share and became known as the Plywood State. Charley's small, intense core struck Cayo Costa and Punta Gorda on 13 August with catastrophic wind damage in Charlotte County, then carried hurricane-force winds across the peninsula past Orlando. The NHC counted 15 direct deaths from Charley, 10 of them in the United States, and estimated total US damage near $15 billion in 2004 dollars, then second only to Andrew. Charley had earlier crossed western Cuba as a major hurricane.

Three weeks later Frances, weakened to Category 2 after raking the Bahamas, moved slowly ashore at Hutchinson Island on 5 September with a 50 to 70 nautical mile wide eye, then crossed the peninsula and made a second landfall in the Big Bend. Its rains spread flooding up the Appalachians, and the NHC counted eight direct deaths and about $8.9 billion in US damage in 2004 dollars. On 26 September Jeanne came ashore near Stuart at almost exactly the same spot as a Category 3 hurricane with 105 kt winds, causing an estimated $6.9 billion in US damage in 2004 dollars. Between them, Gaston's Category 1 landfall in South Carolina on 29 August led to flash floods in Richmond, Virginia, that killed eight people.

Ivan's toll was spread across the Caribbean and the US Gulf Coast. Its northern eyewall passed over Grenada on 7 September, damaging or destroying more than 14,000 homes, and a 3-metre storm surge submerged nearly all of Grand Cayman, where most structures were damaged or destroyed. Jamaica escaped a direct hit but still had at least 47,000 homes damaged. Ivan then came ashore just west of Gulf Shores, Alabama, on 16 September as a Category 3 hurricane, collapsing part of the Interstate 10 bridge over Pensacola Bay and leveling Perdido Key. The NHC put Ivan's direct deaths at 92, including 39 in Grenada and 25 in the United States, and its US damage near $14.2 billion in 2004 dollars; the Caribbean Development Bank estimated a further $1.85 billion in the Cayman Islands, $815 million in Grenada and $360 million in Jamaica.

The deadliest disaster came from Jeanne before it reached Florida. After crossing Puerto Rico, it spent about a day and a half over Hispaniola as a weak but very wet system, and the resulting flash floods and mudslides in Haiti killed more than 3,000 people according to media reports, nearly 2,900 of them in the coastal city of Gonaïves, where some 200,000 people lost their homes or livelihoods.

Ivan's second life and a record year

Ivan's story did not end in Alabama. After becoming extratropical over the Delmarva Peninsula on 18 September, its leftover low-level circulation drifted south off the East Coast, crossed Florida and regenerated into a tropical storm over the Gulf of Mexico on 22 September, finally coming ashore in southwestern Louisiana as a depression on 24 September. A redevelopment like this was almost unprecedented, and forecasters debated whether it deserved a new name before keeping Ivan under the rule that a remnant which redevelops keeps its original name. Counting the whole journey, Ivan existed in some form for 22.5 days and travelled more than 5,600 nautical miles.

The response to Charley, Frances, Ivan and Jeanne became the largest operation in the histories of both the American Red Cross and the Federal Emergency Management Agency up to that time, and the year was the costliest Atlantic season on record until 2005 surpassed it. In the spring of 2005 all four names were retired, tying the then record, and were replaced by Colin, Fiona, Igor and Julia. The NHC also set record low track-forecast errors in 2004, which it attributed partly to the season's many slow-moving storms and deep-tropics tracks that were comparatively easy to predict.