Hurricane Season is here!

Yesterday, Hurricane Dennis slammed into the Florida panhandle and Alabama coast, packing 120-mph winds and dumping heavy rains on areas still reeling from last year's hurricane season. The killer storm had already claimed at least 20 lives in the Caribbean.

Thankfully, Dennis weakened quickly once it came ashore. But the hurricane season is still in its early stages--it runs from June 1 to November 30--and the U.S. National Oceanic and Atmospheric Administration (NOAA) has warned that we're in for another rough year.

According to NOAA administrator Conrad Lautenbacher, "Forecaster confidence that this will be an active hurricane season is very high.

HOW ARE HURRICANES FORMED?

Think of a hurricane as one gigantic heat pump--an engine driven by the energy of ocean water heated by the blazing tropical sun to at least 80 degrees Fahrenheit (27 degrees Celcius).

Such water can make for one heck of a beach vacation. But it also creates warm, extremely humid air that can rise and make big trouble, when warm ocean winds coming from different directions converge and force the humid air upward. As the humid air rises, it cools and condenses into a powerful storm band and releases the latent heat energy of warm ocean water.

Of course, a garden-variety thunderstorm is a far cry from a neighborhood-destroying hurricane. As the humid air rises, it leaves behind a low-pressure area that literally sucks in more warm humid air--more fuel for the storm. If the rising and condensing air encounters more humid air as it rises, and if winds higher up in the atmosphere don't shear the growing storm apart, and if there's a high-pressure area above it, the steamy, sea-stirring storm may become a hurricane.

The high-pressure area above the storm is the hurricane engine's "exhaust pipe," halting the rising air and pushing it out and away, so that even more warm air can get sucked into the space below. In fact, a hurricane's gargantuan winds result from warm air rushing inward to replace the air that's rising up in the center of the storm and, eventually, being pushed out and away high in the atmosphere.

If this whole engine--sucking in humid ocean air, condensing it into a massive storm, and pushing the air away so that more can rush in to take its place--becomes large enough, the rotation of the Earth can take the disturbed area and spin it around, creating that classic, spiral hurricane shape.

Once created, the hurricane engine can draw life from the warm ocean for days. If, however, the hurricane moves over land or into colder areas, removing the warm water that fuels it, the storm will quickly dissipate.

- Christopher Call