Amsterdam News in the Classroom: A Look at Hurricanes
JASMIN K. WILLIAMS Special to the AmNews | 9/22/2011, 11:44 p.m.
The tristate area was recently hit by Hurricane Irene. This was not the first time New York has felt the power of these storms. Hurricane season began June 1 and ends on Nov. 30. Here's a brief look at these powerful storms.
Who could ever forget Hurricane Katrina, which devastated New Orleans in 2005. While Irene was thankfully not nearly as destructive, all hurricanes are powerful and dangerous.
Birth of a monster storm
Hurricanes form far out to sea above warm ocean waters that are at least 80 degrees Fahrenheit. These tropical disturbances usually begin in the Atlantic Ocean off the coast of Africa as a cluster of thunderstorms. Most of these storm systems fall apart, but some organize and begin to increase in size and power, becoming full-fledged hurricanes. This process takes anywhere from a few hours to a few days.
How does the system go from disturbance to hurricane? As the thunderstorm system moves across the ocean, it draws the warm ocean water up into it. That water condenses and forms storm clouds that are fueled by latent heat of condensation. This heat warms the cooler water below it, causing it to rise up into the system. The cycle continues to pull more and more warm air up into it.
As the moist air rises, it collides with the air already in the system. This process creates the converging winds, which are a key part of a hurricane. A steady cycle of condensation, warming, cooling and collision creates the system of thunderstorms and high winds that form the hurricane. The system must have continuous movement of warm air to stay strong and organized.
All storms that form in the Northern Hemisphere rotate counter-clockwise. This is called the Coriolis effect. Storms that form in the Southern Hemisphere (south of the equator) rotate clockwise.
Hitting land causes a hurricane to lose strength. Remember, it gets its power from warm water. But it is when it hits land that it does the most damage, with strong winds that topple trees and destroy property and drenching rains that cause massive floods. A strong hurricane will quickly lose its punch, as Irene did, once it hits land.
Storm systems are categorized based on their wind speed:
- Tropical depression: wind speeds less than 38 mph
- Tropical storm: wind speeds 39-73 mph
- Hurricane: wind speeds higher than 74 mph
Hurricanes are also categorized by wind speed:
- Category 1: 74-95 mph
- Category 2: 96-110 mph
- Category 3: 111-130 mph
- Category 4: 131-155 mph
- Category 5: 155 mph or more
What's in a name? For hundreds of years, hurricanes in the West Indies were named after saints. The United States used to name its storms only after women-Alice was the first human name to be used, in 1959. Men's names were introduced in 1978, with Hurricane Bob (1979) as the first. When a storm is particularly deadly, as was the case with Hurricane Katrina, the name is never used again. Hurricanes are named going in order of the alphabet, using all of the letters except for Q, U and Z.
The nation's deadliest hurricane was an unnamed storm that struck Galveston, Texas, on Sept. 8, 1900. It struck land as a category 4 hurricane and killed 8,000 people.
Here are the names of this year's Atlantic storms:
Arlene, Bret, Cindy, Don, Emily, Franklin, Gert, Harvey, Irene, Jose, Katia, Lee, Maria, Nate, Ophelia, Philippe, Rina, Sean, Tammy, Vince, Whitney
Notice how many of these you hadn't ever heard of before Irene. These systems fizzled out before they became hurricanes.
- Look it up: Use the Internet or other reference source to learn more about hurricanes.
- Talk about it: How did you and your family handle our latest brush with a hurricane? What special preparations did you make?
- Write it down: The Office of Emergency Management suggests that we should always be prepared in case of an emergency. Create your own emergency checklist. What would you include and why?