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Hurricane Gilbert's growth from a harmless low pressure zone off Africa to a ferocious killer in the Gulf of Mexico was fueled by a combination of heat , moisture and wind that baffles forecasters
` ` It's a matter of getting everything together in the right place in the right time , ' ' Gil Clark of the National Hurricane Center said Thursday
` ` It doesn't happen very often .
How it develops , we don't know . ' ' Gilbert came to the attention of center forecasters Sept . 3 as a dry low pressure trough moving west out of Africa
` ` We get 50 or 60 of these off Africa every summer .
About one of six develop , ' ' said Clark .
By Sept . 8 , the system became a depression .
It reached tropical storm status by Saturday and a hurricane Sunday .
A tropical wave becomes a depression when winds start swirling .
When sustained winds reach 39 mph , the system becomes a named tropical storm .
It reaches hurricane status when sustained winds hit 74 mph .
Why Gilbert organized and strengthened while other systems didn't ` ` is a mystery more or less , ' ' said University of Miami meteorology Professor Rainer Bleck
` ` The first part of the summer we were biting our nails , wondering why these ( other ) disturbances didn't develop , ' ' he said Thursday
` ` That's something meteorologists would like to know more about . ' ' But the scientists do know what fuels a budding storm once development begins .
And they know that development is sparked when winds converge , and that growth is affected by time and place
` ` If that happens in an area where there's plenty of moisture in the lower atmosphere ( the bottom 10,000 feet or so ) , this convergence may lead to upward motion and cloud formation , ' ' Bleck said
` ` If clouds form , the heat of condensation in the clouds occasionally provides ` positive feedback ' to the convergence pattern .
That strengthens it , ' ' he said , adding that storms can begin budding only off the equator because of the Earth's rotation .
Eventually , a vortex is created
` ` Any time you contract an air mass , they will start spinning .
That's what makes the tornadoes , hurricanes and blizzards , those winter storms , ' ' Bleck said .
Hurricanes ` ` are useful to the climate machine .
Their primary role is to transport heat from the lower to the upper atmosphere , ' ' he said
` ` The sun puts energy into the water , the top of the oceans and lowest part of the atmosphere .
That has to be distributed from the bottom to higher levels of the atmosphere . ' ' When the depression that would become Gilbert neared Barbados , warm Atlantic waters nurtured it
` ` This time of year in the northwest Caribbean is best for development , ' ' Clark said
` ` If you get a storm in this area in September , when the water's warmest , it can just explode .
This is where Camille formed and exploded , ' ' referring to the 1969 storm that slammed into the Gulf Coast
` ` It is an exciting thing to watch .
If you're on the beach watching the storm surge , it's a different story , ' ' he said .
The hurricane center said Gilbert was the most intense storm on record in terms of barometric pressure , measured at 26.13 inches Tuesday night .
That broke the 26.35 inches of the 1935 hurricane that devastated the Florida Keys .