Homework #6: Answers
1. Hurricane Katrina (HK) occurred during the 2005 season which was
______the most active_____hurricane season of modern times.
2. HK rapidly intensified as it moved over the warm waters of ___the loop current___
in the Gulf of Mexico.
3. Although HK was a powerful Category 5 hurricane in the Gulf of Mexico, it made
landfall as a Category ___3___ hurricane.
4. The National Hurricane Center’s “best track” forecast made 56 hours before landfall
eventually verified as ______exactly correct______.
5. True or False........................ “No one could have anticipated the failure of New Orleans’
levee system” during HK.
False
6. a) The levee system was built to withstand a Category __3__ hurricane.
b) The levees are now being rebuilt to withstand a Category __3__ hurricane.
7. True or False.........Mayor Nagin ordered a mandatory evacuation as soon as it became
apparent that HK, then a powerful Category 5 hurricane, was destined to make landfall
near New Orleans.
False
8. The majority of the levees failed because: a) they were overtopped by the storm surge
or b) they collapsed due to poor construction and maintainance.
b) they collapsed due to poor construction and maintainance
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9. True or False...The Coast Guard and National Guard rescued 58,000 people in New
Orleans.
True
10. During which tropical cyclone were there more fatalities, Hurricane Katrina or the
1970 Bangladesh (Bhola) Cyclone?
1970 Bangladesh (Bhola) Cyclone
11. a) Tropical cyclone frequency has _____remained relatively constant_____ since 1970.
b) Tropical cyclone intensity has ______increased______ since 1970 and “likely”
will continue to _____increase_______ with further global warming.
12. What environmental condition, which has been increasing, is likely most responsible for
this change in tropical cyclone intensity?
Rising sea surface temperatures
13. What other global warming consequence is likely to result in an increase in the impact
of any given tropical cyclone?
Rising sea levels
14. Floods represent the _____ inundation of adjacent land due to overflow from a body
of water (most often river basins and coastal regions)_______(definition).
15. Why have been, and are, river basins home to some of the most highly populated
human civilizations and populations?
The natural occurrence of periodic flooding into river basin flood plains has
provided fertile farmlands, as well as the availability of fresh water and aquatic
transportation for trade
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16. Why does 40% of the global population live within 60 miles of the coast?
The attractiveness of coastal regions for economic reasons (trade centers due to
the availability of global transportation) and, more recently, for their scenic beauty
17. Floods are the ____number two____ weather-related cause of deaths worldwide.
18. a) 44% of all floods and 93% of the flood related fatalities occur in ____Asia_____.
b) What are the reasons for this?
1. Overwhelming portion of population living in large river basins and along extensive
coastline
2. Poor infrastructure
3. Megadeltas
4. Monsoon
5. Topography
19. Flash floods are usually caused by _____slow moving thunderstorms_______.
20. Regional floods are usually of ____longer_____ duration than flash floods.
21. What are four causes of regional floods?
1. Slow moving warm fronts or stationary fronts
2. Rainfall flooding from tropical storms
3. Monsoon floods
4. Flooding from tropical disturbances/ITCZ
22. What type of land use predisposes a region (e.g. Hurricane Mitch/Central America) to
floods, particularly mudslides?
Deforestation for agricultural and development purposes
23. __Crop damage___, __loss of water supply____ and __infectious diseases__ are the three
flooding impacts that are usually the most devastating, particularly in developing
countries.
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24. A monsoon is defined as ______a seasonal shift in the winds_______ which usually results
in a single rainy season (usually during summer).
25. The Asian monsoon is caused by differential heating between __land__ and __ocean___.
26. The increase in precipitation intensity with global warming is most likely due to
increased ____saturation vapor pressure_____ with higher tempereatures.
27. The IPCC indicates that ____an increase___ in flooding events, particularly over the
Asian monsoon region, is “very likely” with global warming.
28. Drought results in ____greater mortality____ globally than any other weather related
phenomenon.
29. What are the three most common causes of drought?
1. Persistent surface high pressure system
2. El Nino/Southern Oscillation (ENSO)
3. Shift of monsoon rainfall to the south and reduction in intensity
30. A shift in the monsoon rainfall in the ___African Sahel___ region from the 1970’s to the
present has resulted in a drought with the largest human impact in recent history.
31. The cause of this drought is a reduction in the temperature contrast between
__the Atlantic Ocean__ and ___the Sahara (desert)__.
32. This drought is the underlying cause of a civil war and “genocide” in __Darfur___.
33. The IPCC indicates there will “likely” be a(n) ____increase____ in drought with global
warming.
34. This change is likely due to strengthening and expansion of ___the ring of semipermanent subtropical high pressure systems.
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