Scientists sceptical of `Year of the Hurricane'

Just as the world is recovering from El Nino and the weather disturbances throughout the globe which emanated from the Pacific…

Just as the world is recovering from El Nino and the weather disturbances throughout the globe which emanated from the Pacific Ocean in 1997, attention is most definitely shifting to the Atlantic Ocean; notably that turbulent cauldron in the Caribbean where hurricanes whip-up and are duly christened with innocuous names which belie their ferocity.

Moreover, scientists at Colorado State University in the US say 1999 is set to exceed the past four years, which have experienced the worst hurricanes since records began. It culminated in 10 hurricanes and three "intensive" hurricane systems (where winds exceed 110 m.p.h.) during 1998. In the difficult process of meteorological prediction, these recent events suggest a pattern, according to atmospheric scientist Prof William Gray. St Stephen's Day saw wind speeds of 109 m.p.h. at Malin Head, the highest in this country since the aftermath of Hurricane Debbie in 1961.

Based on their analysis, scientists predict nine hurricanes and four intensive ones this year. If they materialise in the Caribbean and along the US Atlantic coast, Ireland and western Europe will be buffeted with their after-shocks in the form of Atlantic storms. Another certainty is that when the Pacific cools down (as is happening now), and a cold current known as La Nina asserts itself, it coincides with hurricanes in the Atlantic. There is an observable statistical link between both phenomena but no clear explanation for it, according to Dr Peter Lynch, assistant director of Met Eireann. He is involved in an international investigation, known as Fastex, into the way Atlantic storms originate and develop.

Prof Gray's team believes, however, if the hurricane pattern is sustained, severe winds will continue to blow more strongly and more frequently, topping Mitch which the US administration described as the "worst disaster we have seen in this (northern) hemisphere". It is possible this pattern could persist for decades. Their main concern, he told the Independent on Sunday, is the toll increased activity would have on high-population areas located close to where Atlantic hurricanes rage: notably central American and south-eastern US.

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The team's predictions are based on evaluation of weather phenomena throughout the globe including rainfall in parts of west Africa, the temperature of the Pacific, stratospheric winds blowing from the west, and an active "North Atlantic conveyor belt corridor" which carries warm weather from the Caribbean to east Greenland and returns a cold water current. Global warming may also be a factor. Interestingly, other research suggests no conclusive evidence of seas in the Atlantic getting rougher. no.

Dr Lynch, however, has reservations about the reliability of such long-term predictions. There has been a great thrust in recent years, he notes, in "seasonal forecasting", which was reflected in good accuracy during the El Nino year but the Colorado team had gone beyond this to a yearly prediction. In reality, he added, "Met Eireann would not predict more than one week ahead. We cannot predict whether next winter will be more or less stormy".

Kevin O'Sullivan

Kevin O'Sullivan

Kevin O'Sullivan is Environment and Science Editor and former editor of The Irish Times