U.S.A. is comprised of 52 states which are surrounded by the
Atlantic and Pacific ocean and the Gulf of Mexico.
Lower 50 states have Atlantic Ocean on the East ,Pacific
Ocean on the West and Canada is in the North of America .
Mexico is in the South while
The Gulf of Mexico is in the
Southeast of U.S.A.
• Alaska has the Arctic Ocean
on the north and Pacific Ocean
on the south.
• Hawaii is the chain of islands
surrounded by Pacific Ocean.
STATES THAT BORDER ATLANTIC OCEAN:
New York , North Carolina, South
Carolina, Georgia, Florida , Maryland, Virginia, New
STATES THAT BORDER THE PACIFIC
Alaska, California, Hawaii, Oregon, Washington
STATES THAT BORDER THE GULF OF
The Gulf of Mexico has total area of 1.5 million sq. km.
Alabama ,Florida , Louisiana ,Mississippi and Texas
A disturbance of the normal condition of the
atmosphere, marked by winds of unusual force or
direction, along with heavy rain, snow, hail, thunder, and
lightning, or flying sand or dust.
And Severe Weather” ,
The National Weather
severe weather as:
Hail of greater
than 1 inches in diameter
• Winds of speed greater
than 55 mph
Knox Pam ,2011:Natural Disaster:What Causes Severe
reived at 4 May 2013
CAUSES FOR EXTREME
WEATHER IN U.S.A
The central plains
Other countries are shielded
Size of the U.S
Ocean front property
COMMON TYPES OF STORMS
Tropical cyclones (Hurricanes)
Winter storms derive
their energy from the
clash of two air
and moisture levels.
• Winter storms usually form when an air mass of
cold, dry, Canadian air moves south and interacts
with a warm, moist air mass moving north from the
Gulf of Mexico.
TYPES OF WINTER STORMS
Lake Effect snow
An ice storm is a type of
winter storm caused by
The U.S. National
Weather Services defines
an ice storm as a storm
which can accumulate at
least 0.25 inches of ice on
at a rate of 5 cm per
Temp. -10 ͦC and
wind speed greater
LAKE EFFECT SNOW
Arctic air masses
generally blow from a
west or northwest
direction, causing lake
effect snow to fall on the
east or southeast sides of
They are strong areas of low
pressure that often form
either in the Gulf of Mexico
or off the East Coast in the
Nor'easters are notorious for
producing heavy snow, rain,
and oversized waves that
crash onto Atlantic beaches,
often causing beach erosion
and structural damage.
According to a research paper, “Monitoring and
understanding trends in extreme storms”,
The dominant factors that determine US winter storms
characteristics ( frequency, duration and intensity) are
El Nino and La Nina .La Nina favors northerly storms
bringing intense snow to Northern Midwest and the
northern Rockies, while El Nino favors southern storms
bringing heavy precipitation to southern states.
• Kunkel, Kenneth E., and Coauthors, 2013: Monitoring and Understanding Trends in
Extreme Storms: State of Knowledge. Bull. Amer. Meteor. Soc., 94, 499–514.
doi: http://doi.org/10.1175/BAMS-D-11-00262 x.dRetrieved at 4 May 2013
Tornado is a violent ,low pressure storm relatively small in
Tornados are most common in united states than any other
United states receives 1200 tornado annually .
Tornados in united states can occur at any time but they are
more common in spring .
United states receives many deaths and injuries related with
According to National Oceanic Atmospheric Administration
(NOAA) most of deaths occur because people are not
Florida was the state with most losses.
Low pressure structures that form over warm tropical waters
and have gale force winds near the centre.
Heavy rainfall connected with the passage of a tropical cyclone
can create extensive flooding.
tropical cyclones are important features of the Earth's
atmosphere, as they transfer heat and energy between the
equator and the cooler regions nearer the poles.
HOW DO TROPICAL
Within region of low pressure air is heated over warm tropical
This air rises in distinct parcels causing thundery showers to
These showers come and go they grouped together in to large
masses of thunder storms.
This create flow of very warm, moist air leading to increase of
center of low pressure.
Katrina - 2005 - Katrina was the most costly hurricane on
record causing an estimated $75 billion in damage in Louisiana
Andrew - 1992 - Andrew was a Category 5 hurricane which hit
south-east Florida and south-east Louisiana causing $44,878
million of damage.
The most deadly tropical cyclone ever recorded hit Bangladesh
in 1970 killing approximately 300,000 people.
IS CLIMATE CHANGE AFFECTING
Climate models show that there may be an increase in tropical
cyclone intensity in the future, under nonstop global warming.
However, the models also indicate that tropical cyclone rate
will either remain unmoved or decrease.
A thunderstorm is a kind of storm that generates lightning and
thunder. It is usually accompanied by heavy precipitation
Thunderstorms can create many types of damage weather such
as lightning, hail, tornadoes, straight-line winds, flooding and
Hailstorms are defined as thunder storm that make hail.
Hail is defined as an opening at diameter of 0.2 inches or more.
A derecho is a huge, violent, fast-moving, complex of
thunderstorms that chase one another along a course of at
least 240 miles, with wind gusts of at slightest 58 mph.
A hurricane is a tropical cyclone with winds that have
speed of 74 miles per hour
Hurricanes in Atlantic ocean
Typhoons in Northwest Pacific ocean
Cyclones in South Pacific and Indian ocean
Warm moist air
High temperature (26.5 degrees C or above )
(Hurricane Formation - NOAA - National Oceanic and
STRUCTRE OF HURRICANES
Center portion of hurricane
Low pressure place in hurricane
The eye is typically 20 to 40 miles
Does not forms until winds have speed of 74 mph
Eye wall surrounds the eye of hurricane
Strongest winds and heaviest rains are found
Its Contraction and expansion
Challenges in forecasting the
strength of hurricane
Long curving bands of clouds that spiral around eye wall
Heavy rain and wind are associated with rain bands
Speed of winds within the rain bands decreases outward
Gaps between rain bands are calm having no wind or rain
HURRICANE WIND SCALE
Estimates potential property damage.
1 to 5 rating based on a hurricane's sustained wind
Category 3 and higher are considered major
Category Sustained winds Types of damages due
to hurricane wind
1 74-95 mph
Very dangerous wind
will produce some
2 96-110 mph
winds will cause
157 mph or higher
252 km/h or higher
CAUSES OF KATRINAAND
Katrina was a tropical cyclone drew its energy from warm
waters of Atlantic Ocean.
Sandy also blow through tropics but as the storm moved
northward, it merged with a weather system arriving from
the west and started transitioning into an extra tropical
Difference between katrina and sandy
Tropical cyclone drew their energy
from warm ocean waters
Extra tropical cyclones are fueled
by sharp temperature contrasts
between masses of warm cool air
65 km/h or 500 kilometer
Wind were more intensity but cover
Cover more area
NAMING OF HURRICANES
List of hurricane names for 2013
Andrea, Barry, Chantal, Dorian, Erin, Fernand,
Gabrielle, Humberto, Ingrid, Jerry, Karen, Lorenzo
For formation Hurricanes need
It generally form on tropical ocean where
these two condition exist.
Human activities increase the global warming
which lead to increase in
temperature over the globe.
Variation in temperature in Atlantic increase the
severity of hurricanes over the pervious years
FREQUENCY AND SEVERITY
OF HURRICANES INCREASES
The three main factor of temperature change causes hurricanes
1)Rise in temperature of air and water over the globe.
2)Human activities like deforestation and greenhouse gases.
3)Failure to take action now to lower atmospheric level of
greenhouse gases will responsible for frequent and sever
hurricanes in coming years.
The scientist of Princeton University and the
Massachusetts institute of technology provides the
In coming years the extreme hurricane strike the
united state and coastal area because of variation in
According to statement of professor Michael
“sea level rise and warmer water temperature could
possibly cause a storm that likes of which have not been
Scientist believe that rise of sea level by 2100, cause a
hurricane of century which have not been seen before.
Research evidence shows that increase in temperature
cause a rise of storm surge.
NASA reported that there is increase in temperature of 1
Fahrenheit over the past 100 years on tropical ocean
Green house gases are major contributor increase
in temperature of sea which cause hurricanes.
That there is strong relationship between the
tropical Atlantic sea surface temperature and
Atlantic hurricanes activities.
The rain fall and wind speed also increase by
human activities i.e.1oc increase in tropical sea
hurricanes surface wind speeds increase =1 to 8%
increase rainfall rates =6 to 18%.
Hurricanes in Atlantic ocean
Atlantic hurricanes start from the west coast of Africa
and move west toward United States.
Hurricanes of Atlantic rise in late summer and earlier
Difference in East and
West coast of USA
Atlantic Ocean hurricanes form
which cover the
1)East side of U.S.
2)Northeast pacific basin to the
west of the U.S.
1) The hurricanes form in the tropical and subtropical
latitude when they move toward the west-northwest.
In the Atlantic the hurricanes strike to the U.S east
coast area because of motion.
2) the major factor which is involve is the
difference in east and west coasts of U.S.
The east coast provide the source of warm water
(>80of or 26.5oc)
The formation of hurricanes is also affected because
of ocean clockwise current.
The current move from north to south in the
pacific, whereas on the east coast the warm water
move from south to north from the Gulf flows
• Atlantic Ocean and USA.
hurw.htm.Retrieved at 4 May 2013.
• Causes of Katrina and Sandy.
2012_Sandy.html.Retrived at 3 May 2013.
• Climate Change Cause Hurricanes; U.S.A NEWS.
change-could-cause-killer-hurricanes-in-nyc. Retrieved at 4 may
Deadly Storms in U.S.A. http://www.accuweather.com/en/weather-
news/deadly-super-derecho-strikes- m/67383.Retrived at 3 May
Five Factors Contribute To Increased Severe Weather in U.S.A.
eved at 29 April 2013
Geographical Location of U.S.A.
http://www.mapsofworld.com/usa/.Retrieved at 30 April 2013.
Geography Of Gulf Of Mexico
m.Retrieved at 1May 2013
Hurricanes in east and west coast of USA
at 4 May 2013.
etrived at 2 May 2013
Hurricanes Formation. http://www.nasa.gov/audience/forstudents/k-
4/stories/what-are-hurricanes-k4.html.Retrived at 3 May 2013
Ice storm and Lake Effect Snow.
storms.htm.Retrieved at 2 May 2013
Knox Pam, 2011: Natural Disaster: What Causes Severe Weather.
er.pdf.Retrieved at 4 May 2013
Kunkel, Kenneth E., and Coauthors, 2013: Monitoring and
Understanding Trends in Extreme Storms: State of Knowledge. Bull.
Amer. Meteor. Soc., 94, 499–514. http://dx.doi.org/10.1175/BAMS-
D-11-00262.1 Retrieved at 4 May 2013.
Naming of Hurricanes.
http://www.aoml.noaa.gov/general/lib/reason.html.Retrieved at 3
SAFFIR-SIMPSON Hurricane Scale.
http://www.nhc.noaa.gov/aboutsshws.php.Retrieved at 3 May 2013.
http://dictionary.reference.com/browse/storm.Retrieved at 29 April
Structure of Hurricanes. http://www.nc-climate.
ncsu.edu/climate/hurricanes/structure php. Retrieved at 2 May 2013.
The Hurricane Research Division (HRD) is a part of the Atlantic
Oceanographic and Meteorological Laboratory (AOML).
http://www.aoml.noaa.gov/hrd/tcfaq/G8.html. Retrieved at 4 May
Tornadoes and Tropical cyclone formation in U.S.A
cyclone/247926/Tornadoes.Retrieved at 2May 2013
U.S.A States That Surround Atlantic Ocean
Retrieved at 30 April 2013