STORM SURGE AND HURRICANE SAFETY


Storm surge is a great dome of water
often 50 miles wide, that comes sweeping
across the coastline near the area where the
eye of the hurricane makes landfall. The
surge, aided by the hammering effect of
breaking waves, acts like a giant bulldozer
sweeping everything in its path. The stronger
the hurricane, the higher the storm surge will
be. This is unquestionably the most dangerous 
part of a hurricane. Nine out of ten 
hurricane fatalities are caused by the storm
surge. During the infamous Hurricane Camille in 1969,
 a 25-foot storm surge inundated Pass Christian 
in Mississippi. Lesser height are more usual but 
still extremely dangerous.

Many factors are involved in the formation
and propagation of a storm surge such as
the strength of the storm, bottom conditions
where the surge comes ashore, and the point in 
the storm center in relation to the
shore.         


FLOODS

The floods and flash floods brought by the
torrential rains of a hurricane are dangerous
killers. Even though hurricanes weaken rapidly 
as they move inland, the remnants of the
storm can bring 6 to 12 inches of rain or more
to the area it crosses. The resulting floods
have caused great damage and loss of life.
Hurricane Diane of 1955 caused little damage
as it moved into the continent; but long after
its winds subsided it brought floods to 
Pennsylvania, New York, and New England that
killed 200 persons and cost an estimated
$700 million in damage. In 1972, Agnes fused
with another storm system, flooding creek
and river basins in the Northeast with more
than a foot of rain in less than 12 hours, 
killing 117 people and causing almost $3 billion
damage. Hurricane Beulah of 1967 brought
major floods to southern Texas killing 10
persons and causing millions of dollars
damage.
                 





WINDS

The winds of a hurricane by definition 74
miles an hour or more can be very dangerous. 
For some structures, wind force is 
sufficient to cause destruction. Mobile homes
are particularly vulnerable to hurricane winds.
Some hurricanes spawn tornadoes which
contribute to incredible destruction.

The greatest threat from a hurricane's winds
is their cargo of debris, a deadly barrage of
flying missiles such as lawn furniture, signs,
roofing, and metal siding.





              ACTION CHECKLIST

                          

Here is a list of the many things to consider be-
fore, during and after a hurricane. Some of the
safety rules will make things easier for you during
a hurricane. All are important and could help
save your life and the lives of others.

Stay or Leave?

When a hurricane threatens your area, you will
have to make the decision whether you should
evacuate or whether you can ride out the storm
in safety at home.
If local authorities recommend evacuation, you
should leave! Their advice is based on knowledge
of the strength of the storm and its potential for
death and destruction.

In general:

* If you live on the coastline or offshore islands,
plan to leave.
* If you live in a mobile home, plan to leave.
* If you live near a river or in a flood plain,
plan to leave.
* If you live on high ground, away from coastal
beaches, consider staying.
In any case, the ultimate decision to stay or
leave will be yours. Study the following list and
carefully consider the factors involved especially 
the items pertaining to storm surge.

At Beginning of Hurricane Season (June) Make
Plans for Action

* Learn the storm surge history and elevation
of your area
* Learn safe routes inland
* Learn location of official shelters
* Determine where to move your boat in an
emergency
* Trim back dead wood from trees
* Check for loose rain gutters and down spouts
* If shutters do not protect windows stock boards
to cover glass.

When a Hurricane Watch is Issued for Your Area

* Check often for official bulletins on radio, TV,
or NOAA Weather Radio
* Fuel car
* Check mobile home tie-downs
* Moor small craft or move to safe shelter
* Stock up on canned provisions
* Check supplies of special medicines and drugs
* Check batteries for radio and flashlights
* Secure lawn furniture and other loose material
 outdoors
* Tape, board, or shutter windows to prevent
 shattering
* Wedge sliding glass doors to prevent their lift-
 ing from their tracks


When a Hurricane Warning is Issued for Your
Area

* Stayed turned to radio, TV, or NOAA Weather
 Radio for official bulletins

* Stay home if sturdy and on high ground
 Board up garage and porch doors
 -Move valuables to upper floors
 -Bring in pets
 -Fill containers (bathtub) with several days
  supply of drinking water
 -Turn up refrigerator to maximum cold and
  don't open unless necessary
 -Use phone only for emergencies
 -Stay indoors on the downwind side of house
  away from windows
 -Beware of the eye of the hurricane
* Leave mobile homes
* Leave areas which might be affected by storm
  tide or stream flooding
-Leave early in daylight if possible
-Shut off water and electricity at main stations
-Take small valuables and papers but travel
light
-Leave food and water for pets (shelters will
not take them)
 -Lock up house
-Drive carefully to nearest designated shelter
using recommended evacuation routes.

After the All-Clear is Given

* Drive carefully; watch for dangling electrical
 wires, undermined roads, flooded low spots
* Don't sight-see
* Report broken or damaged water, sewer, and
 electrical lines
* Use caution re-entering home
 -Check for gas leaks
 -Check food and water for spoilage

COMMUNITY ACTION

Beyond individual and family actions during a hurricane emergency
there is much to be done at the community level.  Many
communities on the Atlantic and Gulf coasts have made plans for
action in the event a hurricane threatens, such as delination of
areas to be evacuated, shelter-designations, evacuation routes,
and emergency operations of fire, police, and other public
service units.  

But many exposed coastal communities are not prepared for a
hurricane, and others have waited for disaster's expensive lesson
before taking corrective steps. To encourage community
preparedness, NOAA's National Weather Service has invented a
town, named Homeport, and made it a model of hurricane
preparedness.

Copies of The Homeport story are available
from Superintendent of Documents, U.S.
Government Printing Office, Washington
D.C., 20402. Stock number 0317-0046. Ask
G.P.O. for current price



 TERMS TO KNOW

By international agreement, tropical cyclone is
the general term for all cyclone circulations
originating over tropical waters, classified by
form and intensity as follows:

Tropical disturbance: A moving area of thunder-
storms in the Tropics that maintains its identity
for 24-hours or more. A common phenomenon in
the tropics.

Tropical depression: Rotary circulation at surface
highest constant wind speed 38 miles per hour
(33 knots).

Tropical storm: Distinct rotary circulation, con-
stant wind speed ranges 39-73 miles per hour
(34-63 knots).

Hurricane: Pronounced rotary circulation, con-
stant wind speed of 74 miles per hours (64 knots)
or more.

Small craft cautionary statements. When a tropi-
cal cyclone threatens a coastal area, small craft
operators are advised to remain in port or not to
venture into the open sea.

Gale Warnings may be issued when winds of 39-
54 miles an hour (34-47 knots) are expected.

Storm Warnings maV be issued when winds of 55-
73 miles an hour (48-63 knots) are expected. If
a hurricane is expected to strike a coastal area,
gale or storm warnings will not usually precede
hurricane warnings.

A Hurricane Watch is issued for a coastal area
when there is a threat of hurricane conditions
within 24-36 hours.

A Hurricane Warning is issued when hurricane
conditions are expected in a specified coastal
area in 24 hours or less. Hurricane conditions
include winds of 74 miles an hour (64 knots)
and/or dangerously high tides and waves. Actions
for protection of life and property should begin
immediately when the warning is issued.

Flash Flood Watch means a flash flood is possible
in the area; stay alert.



Flash Flood Warning means a flash flood is im-
minent; take immediate action.

Tornadoes spawned by hurricanes sometimes
produce severe damage and casualties. If a tor-
nado is reported in your area, a warning will be
issued.



                 HURRICANES

Major hurricanes are relatively rare events at any
location. Coastal residents from Brownsville
Tex., to Eastport, Me., have a good chance of
living many years without experiencing one. But
none of our coastal areas are immune. "Not here!
We haven't had a hurricane in years," could be
the most dangerous words you'll ever hear. It's
best to be prepared. This could be the year.

Hurricanes are tropical cyclones in which winds
reach constant speeds of 74 miles per hour or
more, and blow in a large spiral around a rela-
tively calm center he eye of the hurricane.
Every year, these violent storms bring destruc-
tion to coastlines and islands in their erratic path.

Stated very simply, hurricanes are giant whirl-
winds in which air moves in a large tightening
spiral around a center of extreme low pressure,
reaching maximum velocity in a circular band
extending outward 20 or 30 miles from the rim of
the eye. This circulation is counterclockwise in
the Northern Hemisphere, and clockwise in the
Southern Hemisphere. Near the center, hurricane
winds may gust to more than 200 miles per hour.
The entire storm dominates the ocean surface
and lower atmosphere over tens of thousands of
square miles.

The eye, like the spiral structure of the storm, is
unique to hurricanes. Here, winds are light and
skies are clear or partly cloudy. But this calm is
deceptive, bordered as it is by maximum force
winds and torrential rains. Many persons have
been killed or injured when the calm eye lured
them out of shelter, only to be caught in the
maximum winds at the far side of the eye, where
the wind blows from a direction opposite to that
in the leading half of the storm.



Hurricane winds do much damage, but drowning
is the greatest cause of hurricane deaths. As the
storm approaches and moves across the coast-
line, it brings huge waves and storm tides which
may reach 25 feet or more above normal. The
rise may come rapidly, flooding costal lowlands.
Waves and currents erode beaches and barrier
islands, undermine waterfront structures, and
wash out highway and railroad beds. The tor-
rential rains that accompany the hurricane pro-
duce sudden flooding as the storm moves inland.
As its winds diminish, rainfall floods constitute
the hurricane's greatest threat.

The hurricanes that strike the eastern United
States are born in the tropical and substropical
North Atlantic Ocean, the Caribbean Sea, and
the Gulf of Mexico. Most occur in August, Sep-
tember, and October, but the six-month period
from June 1 to November 30 is considered the
Atlantic hurricane season.

The principal regions of tropical cyclone origin
vary during the season. Most early (May and
June) storms originate in the Gulf of Mexico
and western Caribbean. In July and August, the
areas of most frequent origin shift eastward, and
by September are located over the larger area
from the Bahamas southeastward to the Lesser
Antilles, and thence eastward to south of the
Cape Verde Islands, near the west coast of
Africa. After mid-September, the principal areas
of origin shift back to the western Caribbean and
Gulf of Mexico.

On average, six Atlantic hurricanes occur per
year. However, there are significant deviations
from this average. In 1916 and 1950, 11 hurri-
canes were observed, and no hurricanes were
observed in 1907 and 1914. During 1893, 1950,
and 1961 seasons, four hurricanes were observed
in progress at the same time.

Some hurricanes (usually weaker than their
Atlantic counterparts) may strike Southern Cali-
fornia and bring torrential rains to the southwest
U.S.

Hurricanes begin as relatively small tropical cy-
clones which drift gradually to the west-north-
west (in the Northern Hemisphere), imbedded in
the westward-blowing, tradewinds of the tropics.
Under certain conditions these disturbances in-
crease in size, speed, and intensity until they
become full-fledged hurricanes.

The storms move forward very slowly in the
tropics, and may remain almost stationary for
short periods of time. The initial forward speed is
usually 15 miles per hour or less. Then, as the
hurricane moves farther from the Equator, its
forward speed tends to increase; at middle lati-
tudes it may exceed 50 miles per hour in extreme
cases.


The great storms are driven by the heat released
by condensing water vapor, and by external
mechanical forces. Once cut off from the warm
ocean, the storm begins to die, starved for water
and heat energy, and dragged apart by friction
as it moves over the land.




U.S. DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
 Administration
National Weather Service

NOAA/PA 78019

U . S . GOVERNMENT PRINTING OFFICE : 1991 - 293-054 : QL 3


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