Danger in the Caribbean

The region faces the most severe hurricane cycle since the first half of the 20th Century

Por: Dr. José Rubiera.
Director, National Forecast Centre
Cuban Institute of Meteorology

An average hurricane season in the Caribbean basin consists of some 10 tropical storms, of which six reach hurricane intensity. But this is the mean over many decades; when analysing shorter periods, experts have detected 30-40 year cycles during which hurricane activity is particularly intense, including a significant number of events category 3 or higher, which are followed by low-activity cycles lasting approximately the same number of years. Based on the evidence it appears that, after a comparative lull that lasted until the mid 1990s, we are now immersed in an active cycle that calls for greater prevention and mitigation efforts.

Hurricane forecasting is still far from precise in the long term. For instance, the hurricane season is said to start on 1 June and end by 30 November in the Atlantic, Caribbean and Gulf of Mexico; the greatest activity is generally expected between mid August and late October, with a “surge” during the first week of September. However, tropical storms or hurricanes may occur at any time during the season, or even beyond it. While this is unusual, it is not unheard of: in April 2003, tropical storm Ana arose in the Atlantic, a first for that month of the year; and in 1995 hurricane Alice swept through the Lesser Antilles in December, when cyclones seemed as likely as snow in the tropics.

Hence the importance of detecting cyclical patterns in cyclonic activity, a field pioneered by such figures as Professor W. Gray of the University of Colorado and C. Landsea of the U.S. National Oceanic and Atmospheric Administration (NOAA). They have detected, for instance, that these cycles are correlated to periodic changes in water circulation in the Atlantic, not to global climate change.

One of the most active of such cycles took place during the first half of the 20th Century. Examples include the hurricane that devastated Cuba in 1926 and caused 600 deaths, the one that struck Puerto Rico in 1928, and the one that destroyed the capital of the Dominican Republic, Santo Domingo, in 1930.

The hurricane that hit Cuba in 1932 was the greatest natural catastrophe in the history of the island; a tsunami devastated the entire town of Santa Cruz del Sur, killing its 3,000 inhabitants.

Many other severe hurricanes could be listed straight through the 1940s and 1950s. They were followed by a relative lull starting in the 1960s and continuing until the mid 1990s. Not that there were no significant storms during that period, but their frequency and intensity paled in comparison with the previous decades.

Everything seems to indicate that, starting in 1995, a new active cycle has set in. That year happened to be the second most active of the 20th Century, with 19 tropical storms. (1933 had 21 storms.) The eight years between 1995 and 2002 proved to be the most active in recorded history, with 106 tropical storms, of which 62 turned into hurricanes; of these, 29 proved especially severe. One need only think back to hurricanes Mitch and Georges (1998), or hurricane Michelle in 2001.

The most significant fact to bear in mind is that during the last “fallow” period, from the sixties to the mid-nineties, the population that settled in high-risk areas grew significantly, particularly along the coast. The greater number of residents inevitably brought with them much greater investments in real estate and infrastructure, threatening to set back the development of the region, possibly even by decades, should a major catastrophe take place.

In the shorter term, there is some reason for optimism—but only if the population and the authorities of the Caribbean basin take the threat of the current cycle seriously and adopt preventive measures, including the setting up of early warning systems that can alert the population early enough for them to protect their lives and property.

For more information please contact:
José Rubiera
rubiera@yahoo.com
rubiera@ met.inf.cu