Hurricane Karl (1998) - Season Summary - Season Activity

Season Activity

The Atlantic hurricane season officially began on June 1, 1998, with the first tropical cyclone developing on July 27. It was an above average season in which 14 tropical cyclones formed. All fourteen depressions attained tropical storm status and ten of these became a hurricane. Three hurricanes further intensified into major hurricanes. Three hurricanes and three tropical storms made landfall during the season and caused at least 11,636 deaths and $12.2 billion in damage. Hurricane Danielle also caused damage, although it never made landfall. The last storm of the season, Hurricane Nicole, dissipated on December 1, which was the day after the official season ending on November 30.

Activity in the season began slowly, with the first tropical cyclone not forming until July 27. It did not become Tropical Storm Alex until July 29, which was an abnormally late first named storm for an Atlantic hurricane season. After being dormant for about two weeks, Hurricane Bonnie developed on August 19. Thereafter, tropical cyclogenesis became more frequent, with an additional three storms by the end of August. September was the most active month, coinciding with the climatological peak of the season. Six tropical cyclones formed in that month, four of which reached hurricane intensity. On September 26, Hurricane Georges was over the Straits of Florida, Hurricane Ivan was in the North Atlantic, and Hurricane Jeanne was located between Africa and the Lesser Antilles. As such, Karl was one of four simultaneously active hurricanes in the Atlantic, the first such occurrence since August 22 in 1893. However, three hurricanes also co-existed in the Atlantic on September 11 in 1961, with a possible fourth. Following a busy September, activity began slowing, starting in October, when only two tropical cyclones developed. However, both storms became a hurricane, which the second cyclone, Hurricane Mitch, become the most intense, deadliest, and costliest storm of the 1998 Atlantic hurricane season.

Overall, the season's activity was reflected with a cumulative accumulated cyclone energy (ACE) rating of 182. ACE is, broadly speaking, a measure of the power of the hurricane multiplied by the length of time it existed, so storms that last a long time, as well as particularly strong hurricanes, have high ACEs. It is only calculated for full advisories on tropical systems at or exceeding 34 knots (39 mph, 63 km/h) or tropical storm strength.