Transcript What Causes Hurricanes - Central Middle School

Hurricanes ! ! !
Ms. Twardowski
8 Tan
Central Middle School
Word Splash ! ! !
 air pressure
temperature
wind
 climate
forecast
humidity
 dew point
migration
precipitation
FIRST…
 A thunderstorm, a
tropical depression, a
tropical storm, and a
hurricane are ALL THE
SAME! They are just
at varying stages of
size and levels of
dangerousness.
To begin to understand what
causes a hurricane you need to
know:
 When the temperature and dew point are
closer together, there is more moisture in
the air particles. Usually this happens when
the temp. and dew pt. are within FIVE (5)
degrees of each other.
 This means there humidity is higher and
there is a higher chance for precipitation.
Also…
 When the temp. and dew pt. are further
apart, there is LESS moisture in the air
particles.
 This means the humidity is LOWER.
 There is LESS chance for precipitation.
Air Pressure…
 When the air pressure is low and/or
falling…it means it is going toward “bad”
weather.
 When it’s rising and/or high, it’s going
toward “good” weather. (Example, if it is
raining, it will likely stop.)
What causes a hurricane (6
components)?...
 1. Warm ocean water (at least 80 degrees
Fahrenheit).
 2. Large DECREASE of temperature with
altitude (height).
 3. Moisture present in the air (up to a high
altitude)
What causes a hurricane?...
 4. Pre-existing
(already there) near
surface disturbance
(for example, a Lowpressure system like a
thunderstorm).
What causes a hurricane?...
 5. Vertical wind shear
 6. Minimum of 300
miles from the Equator
so the “Coriolis
Effect/Force” can take
effect (see picture at
left).
Hurricanes…
As seen from a satellite…
This is the symbol for a hurricane…
It’s coming!...BTW, a hurricane and a tornado are the same
thing! Tornadoes happen over land, hurricanes over water.
Hurricanes…
 MOST of the damage
is caused by “storm
surge”…when huge
waves are pushed up
onto shore.
Hurricanes…
 It causes flooding and
can cause millions of
dollars worth of
damage. It can also
claim lives.
The aftermath…
 Objects can be thrown
long distances! This is
VERY dangerous!
Hurricane Watches and Warnings…
 Watch: is issued when hurricane conditions
are possible within 24 to 36 hours.
– You should: Have a battery operated radio or tv.
Have a full tank of gas. Bring in outdoor
objects. Board up windows. Store drinking
water. Etc.
Hurricane Watches and Warnings…
 Warning: Is issued when hurricane
conditions (winds of 74 mph or greater, high
water, rough seas) are expected in 24 hours
or less.
 You should: Listen to your radio or tv. Stores
valuables in a waterproof container. Avoid
elevators. Stay inside, away from windows
and glass doors.
Hurricane Catgories
Category
1
Wind
Speed
74-95 mph
Branches break off,
power lines down
Storm
Surge
4-5 feet
2
96-110 mph
Small trees down,
roof tiles blown off
6-8 ft
3
111-130
mph
Leaves off
trees,trees
down,small building
damage
9-12 ft
4
131-155
mph
over 155
mph
Severe damage to
windows,roofs,doors,
flooding,
13-18 ft
Small buildings
destroyed,evacuation
required,major
damage!
over 18 ft
5
Observed
Damage
How do they name hurricanes?
 Since 1953, in the Atlantic Ocean, tropical storms that reach
a sustained wind speed of 39 miles per hour are given a
name, such as "Tropical Storm Fran".
 The first tropical storm of the year is given the name
beginning with the letter "A", the second with the letter "B"
and so on through the alphabet (using alternating men’s
and women’s names).
 Today, the World Meteorological Organization maintains the
lists of Atlantic hurricane names. They have six lists which
are reused every six years.
 Hurricane names that cause MAJOR damage are put on
the “Retired List” and are not used again.
2011 Hurricane Season Names
 Arlene, Bret, Cindy, Don, Emily, Franklin,
Gert, Harvey, Irene, Jose, Katia, Lee, Maria,
Nate, Ophelia, Philippe, Rina, Sean, Tammy,
Vince, & Whitney
 If there are more than 21 hurricanes for this
season, names of the letters of the Greek
alphabet will be used (Alpha, Beta, Delta,
Gamma, etc.)
The Beaufort Scale (wind speed)…
Beaufort Scale (again)