WHAT IS WIND: Wind is a form of solar energy, caused by the uneven warming of the earth's surface. This is why air masses have different temperatures and pressures, and are constantly moving to find a balance. The higher the difference in pressure, the swifter the air moves and the stronger the wind. Mankind has used wind energy for thousands of years, using it to pump water, grind flour, press olives, and even to explore the world in wind-driven sailing ships.
RATING HURRICANES: Hurricanes are categorized according to the strength of their winds according to the Saffir-Simpson Hurricane scale. They are rated from lowest wind speeds (Category 1) to highest (Category 5). But even lower category storms can cause a great deal of damage, mostly from storm surges and the resulting flooding. The worst devastation from hurricane Katrina, for example, occurred when flooding caused the New Orleans levees to fail.
ABOUT TORNADOES: A tornado begins with a thunderstorm cloud, which can build up a lot of energy. If this energy creates a particularly strong updraft of air, it will form a vortex, much like how a whirlpool forms in a draining bathtub. The air is pulled toward the center in a spiral, forming a tornado under the thundercloud. Wind speeds can reach 200 to 300 MPH, and if the dangling vortex touches ground, the combination of the whirling wind's speed, the updraft, and pressure differences can cause severe damage. The path of a tornado is determined by the path of the parent thundercloud, but it will often appear to hop (called a "jumper"). This occurs when the vortex is disturbed, causing it to collapse momentarily and reform.
The Institute of Electrical and Electronics Engineers, Inc.-USA, and American Meteorological Society contributed to the information contained in the TV portion of this report.