near-coastal ocean bottom. The storm surge gives no quarter and it is in the storm
surge that most lives are lost. The horrific cyclone of 1970 killed more than
300,000 people in the low-lying country of Bangladesh. Winds, of course, are also
a major cause of hurricane damage. Winds are strong in a minimal hurricane but
can become incredibly ferocious under Saffir-Simpson scale Category 5 condi-
tions. The power of the wind is a cube of its velocity so that small increases in sus-
tained wind velocities make for huge differences in destructive power. A third type
of damage is flooding caused by copious rains. Hurricanes frequently produce
rainfall totals in excess of 500 mm per day. These rates cause free-flowing streams
to quickly rise and exceed flood levels. Finally, the large-area cyclonic rotation in
hurricanes frequently makes some of its thunderstorms tornadic.
In the United States, there has been an average of about one-and-a-half hurri-
cane strikes per year. Inflation-adjusted damage has been rising and this is because
of the long-term increase in the population and value of structures and possessions.
Hurricane Katrina of 2006 was the most damaging of hurricanes with estimated
losses placed at $125 billion. It came ashore as a strong Category 3 but with a large
storm surge along a heavily populated coast.
The U.S. loss of life has been modest since the unnamed Galveston storm of
1900 that killed over 6,000 people. Even the catastrophe of Hurricane Katrina
was responsible for less than 2,000 deaths. Over the years, knowledge of hurri-
canes has grown and populations receive notice of impending storms days in
advance. Although exact landfall locations cannot be reliably forecast more than
a day in advance, there is enough foreknowledge to evacuate people inland if there
exists an infrastructure with which to quickly remove large numbers of people.
Large evacuations are feasible in developed countries like the United States but
problematic in poor populations such as that of Bangladesh.Hydrologic Cycle
Water is continuously involved in transport and exchanges between ocean, land,
and atmosphere: this is the hydrologic cycle having no beginning or end.Earth
iscoveredbyaworldoceanenergized bysolar energyand causing the cycling
of water out of and back into the oceanic reservoir. Water’s ready ability to gain
and lose energy and change the spatial arrangement between its molecules makes
this possible. As water is able to circulate around the planet it is easy to appreciate
the importance of the hydrologic cycle that providesprecipitationto continental
interiors. Out of sight to the casual observer is water’s role in transporting latent
heat thus having a major impact on the global energy balance and providing180 Hydrologic Cycle