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Understanding Flooding and
Storm Surge: Causes, Impacts,
and Prevention Strategies
by Charles Vinores, MCE, PE, MBA - Envista Forensics
Flooding and storm surges are among the most
significant natural disasters, especially for vulnerable
coastal areas. Flooding occurs when water flows over
or accumulates on land that is normally dry, while a
storm surge is a sudden rise in water levels and wave
action, often associated with hurricanes and severe
storms.
seawater inland, compounding the destruction caused
by hurricanes and cyclones.
Storm Surge: Rise in Sea Level
A storm surge occurs due to the combined effects of
wind, atmospheric pressure, and tidal conditions.
Strong winds associated with a storm push ocean
water toward the shore, resulting in an abnormal rise
in sea level. This effect is intensified by the low atmospheric pressure that accompanies the storm, which
allows the ocean surface to rise even higher.
These events pose serious threats to communities, as
flooding can inundate homes, infrastructure, and
agricultural land, resulting in extensive property
damage and potential loss of life. Storm surges can
lead to rapid and severe coastal flooding, eroding
shorelines and overwhelming of flood defenses. The
combination of these events can devastate local
economies, disrupt ecosystems, and require costly
recovery efforts.
Coastal topography plays a significant role in how
much the surge varies. Some coastal areas experience
less rise than others, meaning surge levels can be influenced by the slope of the continental shelf or shape
of the coastline. A shallow continental shelf tends to
produce a higher surge compared to a steep one.
Causes of Flooding and Storm Surge
When a storm surge coincides with high tide, the
resulting water levels can be catastrophic. Although
surges are most dangerous along the coastline, they
can also be pushed miles inland, putting those who
live further from the coast at risk.
Flood: Water Accumulation
Flooding can occur due to various natural and
human-induced property damages. One of the primary contributors is heavy rainfall, as intense or prolonged precipitation can overwhelm drainage systems
and tributaries, leading to water accumulation, especially in low-lying areas. River overflow often occurs
when there is excessive rainfall or rapid snowmelt,
causing rivers to swell beyond their banks and flood
adjacent land.
Additionally, water levels, particularly those within
tributaries, can be amplified by the heavy rain that accompanies hurricanes, as inland runoff combines with
the surge in bays, river mouths, coastal estuaries,
canals, and wetlands.
Climate Change: Effects on Weather Events
Climate change is worsening the frequency and
intensity of flooding and storm surges. Rising sea levels-a direct result of global warming-raises the baseline height of ocean water, making storm surges even
more destructive. Additionally, warmer ocean temperatures can fuel major storms, like hurricanes and
Nor'easters, intensifying storms, leading to heavier
rainfall and more severe winds.
As water within a river flows downstream, this rainfall
does not always occur in the same location as the overflow, sometimes occurring hundreds of miles away.
Hurricanes and tropical storms produce relatively
large areas of intense rainfall, often leading to regional
flooding; these powerful systems bring torrential rains
and strong winds that can result in widespread damage. Additionally, storm surges-a type of coastal flooding-occur when winds from strong storms push
EXPERT WITNESS JOURNAL
48
DECEMBER 2024
