Hurricanes

Recent events have forced most of us to reflect upon the nature of hurricanes. We now know that a category 2 hurricane can uproot bananas, a 3 grade can lift less securely fastened roofs and a category 4 can destroy 90 % of our housing stock and our vehicles. We have been awakened to the fact that even a distant force 5 hurricane can send sea swells to erode our beleaguered coastline. We are fully aware of the need to cooperate with the National Emergency Management Office (NEMO) in bracing ourselves to cope with these storms. {{more}}
What we do not know is when the next one will strike St. Vincent and the Grenadines. Meteorologists tell us that hurricanes appear to move in cycles of high and low intensity. Since 1995 the Caribbean has been in a high intensity cycle. In the Southern Caribbean Hurricane Lili struck in 2002, Lenny in 1999, Emily in 1987 and Allen in 1980 and before that one has to go right back to Janet in the 1950s. In the 60s and 70s there were no hurricanes at all in our area. So recent events do seem to support the idea of hurricanes being cyclic.
It has also been argued that hurricanes have become more frequent because of global warming. Sea temperatures have increased since 1995. Moreover, the high level winds which can dissipate hurricane patterns have weakened since the 1990s. Climate change, however, is a phenomenon which needs to be measured over centuries and caution should be exercised in coming to any conclusions.
We cannot even be certain where the next one will emerge. Hurricanes normally develop within the latitudes 10 and 30. Ivan however, like Janet, emerged nearer to the equator. An upper level wind called a jet stream pushes most hurricanes north before they reach St. Vincent. In the case of Ivan the upper level trough of low pressure towards which the jet stream blows was further west. This hurricane therefore ploughed on through the Windward Islands before turning.
Not only is the behaviour of hurricanes difficult to predict but, so far, we have not been able to come up with devices that will disperse and destroy them. Interestingly enough, meteorologists expect an El Nino episode in the Pacific and this could disrupt the conditions that have produced a bumper crop of hurricanes in the North Atlantic this year.
The Hurricane Research Division of the US National Oceanic and Atmospheric Administration (NOAA) based in Miami explains that the El Nino would create high level winds which would blow from west to east, contrary to the jet stream, in the Caribbean and North Atlantic. If this indeed is so, there is a strong El Nino, then these shearing winds could literally rip the hurricanes apart.