For the lay person, which is anyone not schooled in the understanding of meteorology and climatology, the terms “typhoon”, “hurricane,” and “cyclone” may have an equally terrifying connotation. Of course, those living in geographical areas were these phenomena occur regularly will have an idea of the difference between the terms because they will tend to get much more information and news of one kind than the others. Their lives are centered around safety aspects concerned with them, just as anyone living in San Francisco for a time will be aware of earthquakes, when and how they occur and the safety measures that are required when one is happening, as well as precautions they must take to prevent significant loss. For those fortunate enough to live in areas where none of these natural phenomena occur, they may be a little vague on the specifics. This article gives a general idea of the differences between a typhoon, a cyclone and a hurricane, without becoming too technical.
The terms typhoon, hurricane and cyclone all relate to violent storms which begin over a specific body of water and then move in a generally determinable direction. Hurricanes and typhoons are both types of cyclones. A cyclone is characterized by the circular movement of air in the same direction as the direction the Earth turns. This movement is limited in area, but can intensify to cover quite a large amount of space, as was seen with the event of Hurricane Katrina, which destroyed a significant portion of New Orleans. As seen with the devastation of New Orleans, cyclones can not only stir up the air, but can also bring up high seas and create driving, destructive storms. Cyclones generally form over areas of low atmospheric pressure, which means that the air is warmer.
The real difference between cyclones, hurricanes and typhoons is that cyclones occurring in the Southern Hemisphere and Indian Ocean are simply called cyclones. Those which form over the large bodies of water in the Northern Hemisphere are divided into hurricanes and typhoons dependent on which side of the International Date Line they are. Hurricanes are called so because they occur on the western side of the Date Line, while typhoons occur on the eastern side. If a hurricane crosses the International Date Line, it will become a typhoon. The reverse is also applicable, although not very common.
To add some further detail, hurricanes and typhoons are only referred to as such when they reach a certain severity. Cyclones are divided into three different categories. The first two, tropical depressions and tropical storms, are cyclones which are characterized by slower wind speeds and the general lack of an eye, amongst other features. When the speed of the wind in a cyclone reaches 74mph or 119km/h, it is classified as either a hurricane or typhoon, depending on the location.
Once explained, it becomes much easier to understand and demystify the terms, hurricane, typhoon, and cyclone. To recap, hurricanes and typhoons are both intense types of cyclones occurring in the Northern Hemisphere. They are similar in all respects, being differentiated only by geographical location. Hurricanes form on the western side of the International Date Line, and typhoons form on the eastern side and are typified by very high wind speeds and an eye.
References:
http://en.wikipedia.org/wiki/Hurricane#Classifications.2C_terminology.2C_and_naming
http://www.wmo.int/pages/index_en.html
http://www.worldweather.org/
