THE BIG IDEA: The Science of Hurricanes

HURRICANE
HURRICANE

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With Hurricane Matthew serving as an impressive front that segued us from warm weather to temperatures considerably cooler, I thought a look at hurricanes and how these massive machines of wind, rain, and power work. Something different for the Big Idea, I know, but intriguing nonetheless.

Let’s get into some serious science because that’s when the fun begins.

Hurricanes all start with air. Air currents flow in a clockwise direction around a high pressure system when you are in the Northern hemisphere, and counter-clockwise around a low pressure system. What causes it to spin like that is called Coriolis force, caused by the rotation of the earth. When you are in the upper northern hemisphere it spins one way, while in the southern hemisphere it spins another.

stormSince we’re in the Northern Hemisphere, we’re focusing on hurricanes. Depending on where you are in the world, tropical cyclones (which is what a hurricane is classified) are referred to as either hurricanes, typhoons, and cyclones. Hurricanes are areas of deep, deep, low pressure, so their winds always swirl counter-clockwise around the center of the storm where the eye is located. Hurricanes impacting the East Coast usually have a northwesterly track—they always go up in that general direction along Florida, Georgia, the Carolinas, and so on. The windspeed of the hurricane’s northeastern side tend to clock in faster wind speeds because—and get ready as we are about to do some math here—you calculate the speed the storm’s eye is moving plus the speed of the storm’s rotation. On the hurricane’s opposite side, speeds move slower because the two speeds are going to subtract velocity.

For example, if you have a hurricane moving at 14 miles per hour and it is spinning at 105 miles per hour on one side, the wind speeds will be 119 miles per hour on the fast side. The slow side will be 91 miles per hour. So you get different wind speeds depending on where you are.  

Still with me? Fantastic. See—math doesn’t always have to be tough.

Now let’s talk about storm surge. Remember, hurricanes happen in a low pressure zone which means air pressure is not pushing down against the ocean as it would on average. Because of this, you end up having the water in the eye of the hurricane as much as ten feet higher than average because of the considerable lower pressure. That ten feet surge of water when a hurricane makes landfall could create a flooding condition. Particular if a storm makes landfall at the time of high tide.

Finally you have the turbulence happening on the edges of the hurricanes. All that rough wind working in circular patterns tend to spawn tornadoes which is why tornado watches are usually put into effect. They tend to be weak ones, but still with a hurricane’s wind currents as they are it’s not a day you’d want to go fly a kite or enjoy a leisurely stroll through. That’s why I find what the National Oceanic & Atmospheric Administration do when a hurricane is making its way to the East Coast just amazing. While satellites have completely changed the way we track storms, there is still a need for barometric pressure and other storm qualities that satellites cannot tell us. This is why NOAA’s Hurricane Hunters fly into a hurricane in order to get this data. The flight in is pretty amazing, according to pilots. First, the Lockkheed WP-3D Orion flies through a hurricane’s rainbands and the eyewall where a lot of turbulence occurs. Even with winds reach as much as 200 mph at flight level, the Orion is so fortified that the pilots don’t feel it. They do the   updrafts and downdrafts, however.

So the next time you track a hurricane, just know there’s a lot of science happening in front of you. It’s a pretty amazing event, and worth watching. From a safe distance, of course.

 


 

shurtz.jpgA research physicist who has become an entrepreneur and educational leader, and an expert on competency-based education, critical thinking in the classroom, curriculum development, and education management, Dr. Richard Shurtz is the president and chief executive officer of Stratfdord University. He has published over 30 technical publications, holds 15 patents, and is host of the weekly radio show, Tech Talk. A noted expert on competency-based education, Dr. Shurtz has conducted numerous workshops and seminars for educators in Jamaica, Egypt, India, and China, and has established academic partnerships in China, India, Sri Lanka, Kurdistan, Malaysia, and Canada.

 

 

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