Hurricanes are enormous tropical storms that can generate wind speeds of more than 160 miles an hour and can release more than 2.4 trillion gallons of rain each day. Hurricanes develop as a result of tropical disturbances over ocean waters whose surface temperature is at least 80 degrees Fahrenheit. When a tropical storm generates wind speeds of at least 74 miles per hour, the storm is considered a hurricane and rated on a scale of 1 through 5 on the Saffir-Simpson scale, which measures storms based on size, strength and intensity.
For hurricanes to form, the air above the ocean and the surface temperature of the water must be very warm, and thus hurricanes generally develop in regions with these warmer conditions. The conditions in the tropical portions of the North Atlantic Ocean are highly conducive to the formation of hurricanes. Coastal areas affected by tropical storms in the North Atlantic include the east coast of North America, the Gulf of Mexico, the Caribbean islands and the northern edge of South America.
Although hurricanes can technically occur in any region on the planet, according to the Weather Research Center, about 75 percent of all hurricanes develop in the Northern Hemisphere. Thus, some of the northern regions of the Pacific Ocean generate numerous hurricanes. The eastern North Pacific has a high frequency of hurricanes, and this area stretches from the west coast of Mexico to 180 degrees west longitude. The western North Pacific also has the conditions necessary to generate hurricanes, and this part of the globe extends from the Philippine Islands and the South China Sea to 180 degrees east longitude. Hurricanes can also form in the South Pacific Ocean, ranging from eastern Australia to about 140 degrees west.
What hurricanes are called depends on the location where they form. For instance, tropical hurricanes with massive wind speeds in the northern Indian Ocean and in the Bay of Bengal are considered cyclones, and the same storms are called typhoons in many areas of the western Pacific Ocean, especially Japan.