Hurricanes form between the months of June and November because they need to form over warm water. When the water is warm enough, it evaporates into the atmosphere, where winds push the moisture and air until it becomes a storm cloud. When enough storms coalesce, they become a very powerful type of storm known as a “tropical storm.” When a tropical storm becomes powerful enough, with winds over 74 mph, it officially becomes a hurricane.
While the hurricane is forming, winds push the storm clouds into a spiral. In the northern hemisphere, the spiral rotates counterclockwise, while below the equator they rotate clockwise. The spiral rotates around the center, or eye, of the hurricane, which is generally free of storm activity. The wall of the eye, however, is the most violent part of the hurricane, with the strongest winds.
Hurricanes are exceptionally large, reaching over 400 miles wide. The eye itself is often 20 or 30 miles wide. Despite their bulk, scientists measure hurricanes on their strength and wind speed rather than width, categorizing them using the Saffir-Simpson Hurricane Scale or the Saffir-Simpson Hurricane Damage Intensity Scale. Both scales put hurricanes into categories 1 to 5, with 1 being the weakest hurricanes and 5 being the strongest. The Saffir-Simpson Hurricane Scale uses factors such as barometric pressure and wind speed to classify storms, while the Saffir-Simpson Hurricane Damage Intensity Scale takes factor such as property damage and flooding into account, much like the MMI Scale for earthquakes.
Since hurricanes form over warm water, do you believe that global warming will increase the size, intensity, or number of hurricanes in the near future? What else might contribute to the formation of hurricanes? Do you think that it’s possible for humans to influence the formation of these storms?
Sources:
http://kids.earth.nasa.gov/archive/hurricane/creation.html
http://www.komonews.com/news/archive/4097441.html
http://www.dimensionsguide.com/size-of-a-hurricane/
http://www.windows2universe.org/earth/Atmosphere/hurricane/formation.html
-Adrianna, Anna