Other U.S. Cities Prone to Natural Disasters
By: Mark Bloomer, Meteorologist
The crisis that hit New Orleans
at the end of August was an event emergency planners had been concerned about
for many years. Much of the city is below sea level and when hurricane Katrina
hit, the storm surge combined with rough seas caused breaks in the levee that
flooded the city. The storm was well forecasted; however the magnitude of the
disaster was greater than anything emergency responders had dealt with in the
past. It left emergency planners asking how a response system could be
organized to function much more efficiently in the event of another great
One of the questions forecasters and emergency planners may
be asking is “what kinds of disasters are other cities vulnerable to?”
New Orleans is not the only city
vulnerable to large scale natural disasters. Many other American cities are
prone to a major natural crisis including the three great cities of New
and Los Angeles. It may seem gloomy
to think of the potential for great disasters, but maintaining an awareness
of what the forces of nature can do will keep both emergency planners and
the civilian population aware and prepared. I am going to take a look at some
cities and cite some foreboding concerns that
each may need to consider.
New York City is
dangerously at risk for a serious coastal flood in the Long Island Sound. The
occurrence of an extreme tide requires special conditions combining a very
strong Nor’easter with an astronomical high tide. Very strong Nor’easters, the
kind which produce wind fields around 70 knots in the open water, occur a
couple times a year in the northeast. The Nor’easters that produce the highest
storm surges in Long Island Sound take a track close to eastern Long
Island producing a northeast wind. The force of the wind upon the
water combined with an aquatic Coriolis force known as Eckman transport acts to
push the waters at right angles to the wind field. This carries the water in
toward the land resulting in a tide much above normal. Super astronomical tides
most commonly occur either during spring nights at the time of the full moon or
during fall days at the time of the new moon. The combination of a very strong
Nor’easter taking the right track and an extreme spring tide are very rare, but
could be catastrophic when they occur. The New York City
subway system, and many coastal homes, could be submerged during an event of
this kind. Being aware that an event like this is possible can help forecasters
and emergency responders prepare well ahead of time. Plans to evacuate the New
York City subway system and coastal New
York and Connecticut
should probably be put in place incase an extreme tidal flood ever occurs.
Chicago is at
risk for a great blizzard which could strand hundreds of thousands of motorists
if it hit with the right intensity and at the right time. One of the scenarios
for very heavy snow in Chicago
would be a low center slowly tracking northeast into western Ohio.
A storm in this position may result in a north northwesterly wind over southern
Wisconsin and northern Illinois
and a north northeasterly wind over Lake Michigan
resulting in strong coastal surface convergence near Chicago.
Sharp surface convergence combined with vigorous upper level dynamics could
combine to generate very heavy snowfall of 2 to 3 inches an hour for several
hours in metro Chicago. Snowfall of
this intensity can accumulate on road surfaces faster than snow removal crews
can clear the roads. This would cause traffic to come to a stand still
stranding commuters for hours or even days and putting them at risk for
hypothermia or carbon monoxide poisoning. Awareness of this scenario can put
emergencies planners including forecasters and local officials in a position of
readiness to close roads ahead of time should this ever occur.
is at risk for a serious flash flood similar to the kind that hit Rapid
City in 1972, Big Thompson in 1976 or Fort
Collins in 1997. A large thunderstorm complex stationed
over Boulder Canyon
for several hours, producing close to a foot of rain, could send a surge down
the narrow Canyon taking out much of downtown Boulder.
Other potential natural disasters include earthquakes and
tsunamis along the west coast, fires in California
and the Rockies and great tornadoes in the plains.
For many of these disasters, it’s not a matter of if they
will occur, but when they will occur. Being aware of the risks can prepare
cities ahead of time for their potential. New York City
needs a very close and cooperative line of communication between the National
Weather Service and the New York City
transit authority. The transit authority has to have a plan for stopping the
trains and getting people out to the streets above in hour’s notice of a flood.
The City of Chicago and the cities
of the northeast have to strategize a means for getting people off the roads
before a blizzard. Boulder needs a
flash flood warning system and an evacuation plan in the event of a flood.
Preparation for a natural disaster must occur at many levels.
Being aware of the risks that each city or location has is the first step.
Having the forecasters and observing equipment in place to forecast and issue
warnings is another important element. Aggressive communication of the warnings
is essential for making sure that everyone who needs to be warned receives
the warnings and is aware of how they need to respond. The infrastructure
of the town or city should be designed to allow people to evacuate and responders
to enter in a rapid and efficient way. There are many areas vulnerable to
a variety of natural disasters. But being aware is the first step to being
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