Wind Basics Hurricane Tornado Wind / Hail Thunderstorm History / U.S. Hurricane Preparation Call Center Certification

[ Hurricane ]

Throughout the last 10 years, damage from hurricanes has been soaring off the charts. An estimated 290 billion dollars in catastrophe claims has been written in the U.S. alone. Two trends are largely responsible for the growing cost of windstorm disasters. One, rapid coastal development is bringing more people and expensive infrastructure into vulnerable areas. And two, hurricanes are growing stronger and lasting longer, fueled by higher sea surface temperatures. They are also widening their geographic range, invading areas previously considered safe from extreme activity.

The storm activity in the last decade was not only some of the most violent, but also the most frequent.

Over the last three decades, tropical ocean surface temperatures have risen by nearly 1 degree Fahrenheit (half a degree Celsius), an increase of a scale not seen in at least 150 years. As global temperatures continue to rise we can expect more hurricanes reaching top-rated Categories of 4 and 5.

Hurricane Anatomy

(Top) Surrounding the eye of the hurricane is a ring of thunderstorms, called the eyewall. Rainbands surround the eye of the storm in concentric circles. In the eyewall and in the rainbands, warm, moist air rises, while in the eye and around the rainbands, air from higher in the atmosphere sinks back toward the surface. The rising air cools, and water vapor in the air condenses into rain. Sinking air warms and dries, creating a calm, cloud-free area in the eye.

(Middle) Low pressure at the ocean surface in the heart of the hurricane draws in surrounding air. These spiraling winds pick up speed as they approach the eye, pulling more heat and moisture from the ocean surface.

(Bottom) The stronger the convection in the thunderstorms becomes, the more rain they produce. The more rain they produce, the more heat they release into the surrounding atmosphere, further fueling the storm.

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