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What causes flooding?
Flooding isn't just a threat to people
living near water. It happens all across the country. In all regions,
in all climates, in a variety of ways. Take a look at some of the
causes of flooding:
Storm Surge
Storm surge is a large dome of water, often 50 or more miles
wide, that sweeps across the coastline near where a hurricane makes
landfall. Storm surge is the greatest threat to property and life
along the effected coast.
Flash Flooding
Intense rainfall in a brief period leaves more water than the
ground can absorb. When this happens, flash flooding can occur.
Flash floods occur with little or no warning, move at very fast
speeds and can reach a peak in a few minutes. They can roll rocks,
tear out trees and destroy buildings and bridges.
Mudslides
Mudslides result from long, heavy rains on hillsides and mountainsides.
The water saturates the soil and acts like a lubricant, causing
soil, large rocks, boulders, and homes to slip free.
Snowmelt
This type of flooding comes when higher-than-normal spring temperatures
cause snow to melt rapidly. The excess water is too much for the
frozen ground to absorb.
Ice Jams
On frozen rivers, melting snow and heavy rain break the ice
into large chunks. These chunks float downstream, often piling up
at bridges, dams and narrow passages. These ice jams can force water
to overflow riverbanks, flooding nearby homes and businesses.
Nature isn't the only cause of flooding.
New construction and paving alter land's ability to drain properly.
As a result, run-off is increased two to six times over what would
occur on natural terrain. Areas that were initially zoned as low-risk
can quickly become high-risk as urban development alters typography.
The National Flood Insurance Program
(NFIP) legally defines a flood as follows:
Under
the National Flood Insurance Program (NFIP) a flood is defined as
a general and temporary condition of partial or complete
inundation of normally dry land by:
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The
overflow of inland or tidal waters.
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The
unusual and rapid accumulation or runoff of surface waters
from any source.
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Mudslides
(i.e., mudflows) which are proximately caused by flooding, as
defined above and are akin to a river of liquid and flowing
mud on the surfaces of normally dry land areas, including your
premises, as when earth is carried by a current of water and
deposited along the path of the current.
-
The
collapse or subsidence of land along the shore of a lake or
other body of water as a result of erosion or undermining
caused by waves or currents of water exceeding the cyclical
levels which result in flood as defined above.
To
qualify as a general and temporary condition, the flood must
affect either two or more adjacent properties or two or more acres
of land and have a distinct beginning point and ending point.
Also, to qualify, the flood waters
can only be surface water that covers land that is normally dry.
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