AdriansWeather.com

Elements of a Storm

1. EXHAUST - Hot air is drawn into the atmosphere.

2. STORM CLOUDS - Spiral in upper atmosphere.

3. EYE - Cool air descends into the 20-mile-wide eye, creating a small center of calm weather.

4. EYE WALL - The storm's fiercest winds.

5. SPIRALING WINDS - In the hurricane's lower realms, air flows in towards the center and whirls upward. These counterclockwise winds gain speed as they approach the eye, like a whirlpool. The narrower the eye, the stronger the wind.CLICK HERE for an interactive version with more detail.

STAGES OF DEVELOPMENT
(from tropical depression to hurricane)

Hurricanes evolve through a life cycle of stages from birth to death. A tropical disturbance, in time, can grow to a more intense stage by attaining a specified sustained wind speed.

Hurricanes can often live for a long period of time -- as much as two to three weeks. They may start as a cluster of thunderstorms over the tropical ocean waters.

Once a disturbance has become a tropical depression, the amount of time it takes to achieve the next stage, tropical storm, can take as little as half a day to as much as a couple of days. Or, it may not happen at all. The same may occur for the amount of time a tropical storm needs to intensify into a hurricane.

Atmospheric and oceanic conditions play major roles in determining these events.

Tropical Depression Stage

Once a group of thunderstorms has come together under the right atmospheric conditions for a long enough time, they may organize into a tropical depression. Winds near the center are constantly between 20 and 34 knots (23 - 39 mph).

A tropical depression is designated when the first appearance of a lowered pressure and organized circulation in the center of the thunderstorm complex occurs. A surface pressure chart will reveal at least one closed isobar to reflect this lowering.

When viewed from a satellite, tropical depressions appear to have little organization. However, the slightest amount of rotation can usually be perceived when looking at a series of satellite images. Instead of a round appearance similar to hurricanes, tropical depressions look like individual thunderstorms that are grouped together. One such tropical depression is shown here.

Tropical Storm Stage

Once a tropical depression has intensified to the point where its maximum sustained winds are between 35-64 knots (39-73 mph), it becomes a tropical storm. It is at this time that it is assigned a name. During this time, the storm itself becomes more organized and begins to become more circular in shape -- resembling a hurricane.

Hurricane Stage

As surface pressures continue to drop, a tropical storm becomes a hurricane when sustained wind speeds reach 64 knots (74 mph). A pronounced rotation develops around the central core.

Hurricanes are Earth's strongest tropical cyclones.

A distinctive feature seen on many hurricanes and are unique to them is the dark spot found in the middle of the hurricane. This is called the eye. Surrounding the eye is the region of most intense winds and rainfall called the eye wall.

Large bands of clouds and precipitation spiral from the eye wall and are thusly called spiral rain bands.

The Eye of the Hurricane
(the center of the storm)

The most recognizable feature found within a hurricane is the eye. It is found at the center and is usually between 20-50km-in-diameter.

The eye is the focus of the hurricane, the point about which the rest of the storm rotates and where the lowest surface pressures are found in the storm. The image below is of a hurricane (called cyclone in the Southern Hemisphere). Note the eye at the center.

Located just outside of the eye is the eye wall. Eye walls are called as such because oftentimes the eye is surrounded by a vertical wall of clouds. The eye wall can be seen in the picture above as the thick ring surrounding the eye.

This is the location within a hurricane where the most damaging winds and intense rainfall is found and is the hurricane's most devastating region.

Hurricane Camille was one of ß hurricanes to make landfall on the U.S. mainland in the Twentieth Century as a Category 5 storm on the Saffir-Simpson scale. Only the 1935 Florida Keys hurricane was more intense.

Surge is the rise in water level caused by the wind and pressure created by a hurricane. When the hurricane's swirling winds push ocean water shoreward, saltwater flooding often results. Surge can drive beachfront water levels to 15 feet (or more) above normal, often pushing water much farther inland. When surge occurs during a high astronomical tide, the impact is significantly worse.

In 1969, one of the most infamous hurricanes, Camille, produced the highest surge in record in the United States. The hurricane brought a surge as high as 25 feet to the region between the Mississippi cities of Pass Christian and Biloxi. Surge and battering winds washed away piers, boats, waterfront homes, and businesses.

The destructive force of hurricane waves is determined by its winds -- their speed, how long they have been blowing, and how far they extend over open water. The effect of waves upon coastlines also depends on the way the ocean floor is sloped. The steeper the slope, the more vulnerable the area is to high waves.

"Moving water is unbelievably powerful," says John Hope, hurricane expert at The Weather Channel. "A cubic yard of water weighs about 1,700 pounds and is virtually incompressible. So when you are impacted by a wave, the force is just unbelievable And no structure can withstand that."

A typical hurricane produces six inches to twelve inches more rain after landfall, depending on its speed of motion. Slow-moving storms can produce much more, which can leave inland locations inundated and thousands of people at risk.

The awsome force of a hurricane should never be taken for granted.Its important to respect nature's potential to change landscapes and lives right here,right now,you've got the power-take control and immerse yourself in natures strength and majesty.CLICK HERE