Hurricane Katrina Video Questions PDF

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Hurricane Katrina video questions...

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GEOG 2152: Geography of Hazards

Video: Hurricane Katrina

1. What is a tropical depression? Describe the origins of Hurricane Katrina. - Katrina formed from a tropical wave that had moved off the coast of Africa and then developed into a tropical depression. - Katrina begins as a small storm called a tropical depression, a center of low atmospheric pressure. In the warm waters of the eastern Atlantic, water vapor rises from the ocean then cools which forms clouds and releases heat energy which fuels the storm. - When the rush of air hits the stratosphere, it flattens out and the storm starts turning counter clockwise. - As soon as the winds reach 39 miles per hour, the depression is called a tropical storm.

2. What were the government standards for the construction of the concrete levees? - After Hurricane Betsy in 1965, the government set standards for the levees. - The congress provided the Army Crops of Engineers with funds to upgrade the levees to withstand a Category 3 hurricane and no more.

3. Why did the wetlands begin disappearing after the levees were built? How have disappearing wetlands increased the vulnerability of New Orleans? - Before the levees, when the Mississippi river flooded the wetlands were strengthened and replenished. - The wetlands protected New Orleans against hurricane storm surges, soaking up the violent waters like a sponge, while stands of cypress trees acted as a windbreak. - The wetlands began disappearing after the levees were built because the levees stopped the rivers from flooding which starved the wetlands of new soil and started disappearing at an alarming rate.

- The depleted wetlands are more vulnerable to the encroachment of saltwater from the Gulf, which kills most freshwater plants. Also, as wetlands disappear storm surges rise, putting New Orleans at an even greater risk.

4. How did the workers repair the breaches in the levees? How long did it take to finally pump all the water out of the city? - The workers used sandbags to repair the breaches in the levees. It took them over a month before the city is completely dry. 5. Why did the levees fail in New Orleans? - In New Orleans, a wave overtopped the Category 3 levee walls by more than 5 feet, scouring their foundations and pushing them aside. Overtopping was the main reason the levees had failed around the Lower 9th Ward. - The levees in downtown New Orleans underwent a pressure burst  they were undermined by their own foundations: soft peaty soil, no match for the force of water. In other words, the floodwall failed at the base....