Hurricane Andrew, which ripped across southern Florida in 1992 before slamming into Louisiana, was blamed for 65 deaths and caused more than US$30 dollars in damage.

Credit: NASA

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MIAMI: The Pacific's El Niño ocean-warming phenomenon has resulted in an especially calm Atlantic hurricane season – a welcome respite for the Caribbean and southeastern USA.

There have only been two hurricanes in the 2009 Atlantic season, which runs from June 1 to late November 30, but normally peaks in September and October.

Little activity expected

"We were expecting very little activity this season," said Lixion Avila, a weather expert at the U.S.’s Miami-based National Hurricane Centre. "This happens when the El Niño phenomenon is present in the Pacific, the water warms up there, and that leads to hurricanes forming there and not in the Atlantic."

Hurricane Bill reached powerful Category Four intensity on the five-point Saffir-Simpson scale in mid-August. It bypassed most of the Caribbean and the U.S. east coast, making landfall in southeastern Canada and causing modest damage.

Hurricane Fred formed in the Atlantic in early September, but petered out over the ocean before making landfall.

Every three to six years

Every three to six years, water currents shift along the equator in the Pacific and the ocean warms a few degrees, a phenomenon dubbed El Niño – Spanish for "the boy," a reference to Christ the infant because the warming was first noticed around Christmas in Peru (see "How the El Niño cycle works", Cosmos Online).

The El Niño effect was powerfully demonstrated on Saturday after warm waters prompted Hurricane Rick to roar to top Category Five status as it barrelled up Mexico's Pacific coast.

This hurricane season "could end with no impact against the U.S. nor the Caribbean," noted William Gray, a hurricane expert at Colorado State University who has been forecasting hurricanes for 25 years.

El Niño conditions in the Pacific "result in a higher vertical wind shear over the Atlantic region, which is considered to be unfavourable to hurricane formation and intensification," said Shuyi Chen, a meteorologist and oceanographer at the University of Miami.