Hurricane is the common name given to a
tropical storm formed over the
Atlantic with winds in excess of 74mph. The very same
storms are called
typhoons if they form over the
Pacific or
Cyclones if they form over the
Indic Ocean or northeast of
Australia.
Hurricanes always form near the equator line, fueled by high water temperatures and the coriolis effect. They follow a somewhat predictable path, and are carefully observed by satellites whenever they move close to populated areas.
The strength of a hurricane is measured according to the Simpson Saffir Scale, being category 1 the mildest and 5 the most intense. Hurricanes get human names, from a list that is "rotated" every six years. If a given hurricane causes considerable impact on the society, its name is removed from the list and never reused.
A common misconception is to confuse hurricanes with tornados. Hurricanes are large storms that have the capability of crossing oceans. You can only appreciate their circular nature when you see them from a satellite. Tornados on the other hand, happen on a much smaller scale, being visible as the traditional spinning funnel of dirt or water that typically lasts for minutes or hours. It's very common for hurricanes to spawn tornadoes, increasing even more their destructive powers.