Transcript Hurricane and Tornado Notes

Natural Disasters Vocabulary
 natural disaster
 model
 hurricane
 Evidence
 tornado
 earthquake*
 storm surge
 tsunami*
 droughts
 volcanic eruption*
 flood
 convergent boundaries*
 wildfire
 divergent boundaries*
 sink hole
 transform boundaries*
Natural
Disasters
Hurricanes
 Word originates from the Greek
word cyclone which translates to “an
object moving in a circle”.
 They are called tropical cyclones but
in the North Atlantic ocean and
Eastern Pacific they are referred to
as Hurricanes.
Hurricanes
 Hurricanes are very large and violent
tropical storms, which can start as
small thunderstorms over warm
water as air pressure at the ocean’s
surface drops.
 Heat from the water fuels the storm
and can cause winds and moisture to
swirl upward and increase its
strength.
How are hurricanes formed?
 There are specific conditions that must be present
in order for a hurricane to develop:
 Water Temperature: warm waters (at least 80
°F) thru a depth of about 150 ft.
 Humidity: moist air near the troposphere
 Location: minimum distance of 300 miles from
the equator (5 °N – 30 °N)
 Wind: low- mid shear winds (23mph or less),
with winds facing vertically in same direction
 Air Pressure: low
Parts of the Hurricane
Hurricanes (cont.)
 Hurricanes usually form early summer
when the sun heats huge masses of
moist air up until the end of fall (June –
November).
SEE DEMOSTRATION #1
SEE DEMOSTRATION #2
 The calm center of a hurricane is called
the eye. Although, this is also the most
dangerous part, since the eye wall
surrounding it has high winds.
WATCH HURRICANE AND WEATHER VIDEO
Tracking a Hurricane:
 We can track the path of a hurricane at
home if we know how to use a map to
find coordinates.
 Longitude lines are those that run
vertically (up and down) use east and
west to describe. Ex. y axis
 Latitude lines are those that run
horizontally (side to side) use north and
south to describe. Ex. X axis
Tracking a Hurricane:
 When you write coordinates you first write
latitude first then longitude. You must also
include direction (N,S, E, W) because there
are two of every coordinate; above and
below the equator
 Let’s practice (25N, 80W) (19N, 70W)
Hurricane Hunters
 Hurricane Hunters use specialized
planes that are part of the U.S.
Air force assigned to gather
information about tropical
storms.
 Their information is sent to the
NHC where it is fed into the
computer forecast models so that
a prediction can be made!
National Hurricane Center
 The National Hurricane Center is responsible for
developing a forecast track and issuing any
advisories or warnings. They use the information
from the Hurricane Hunters GPS sonar.
 Tracking: in order to create a possible hurricane
track, the NHC takes into consideration all
conditions surrounding the hurricane such as high
and low pressure systems that can change the
details of the hurricane.
How do we know where the hurricane
is going?
Statistical Models:
based on historical
relationships between
storm behavior and
storm specific details
(location & date)
Dynamical Models:
numerical model
that uses physics to
solve equations of
motion in the
atmosphere
Statistical
Dynamical
Model: combines
both physics and
history to create
a forecast model
Forecast Models
Major Hurricanes
Hurricane Andrew:
 large and ferocious hurricane that
brought economic devastation along a
path through the northwestern
Bahamas, the southern Florida
peninsula, and south-central Louisiana
 damage in the United States is
estimated to be near 25 billion, making
Andrew the 2nd most expensive natural
disaster in U.S. history
Major Hurricanes
Hurricane Andrew:
 struck southern Dade County, Florida, especially
hard, with violent winds and storm surges
characteristic of a category 5 hurricane on the
Saffir/Simpson Hurricane Scale, and with a
central pressure (922 mb)
 In Dade County, the forces of Andrew resulted in
15 deaths and up to one-quarter million people
left temporarily homeless. An additional 25 lives
were lost in Dade County from the indirect effects
of Andrew’s aftermath. However, the direct loss
of life seems remarkably low considering the
destruction caused by this hurricane.
Staying Safe in a Hurricane
 Major dangers:
 High winds
 Flooding
 Pounding waves/Storm Surge
 Tips to staying safe:
 Leave areas that are in the path of a hurricane
before it strikes
 Find shelter in a strong brick or stone building on
high ground
 Stay away from windows and doors
 Keep rope, extra food and water, a flashlight, a
battery-operated radio, and if possible corded
phone and/or cell phone with you.
How are Hurricanes and Tornadoes
classified differently?
Hurricanes
(Saffir-Simpson Scale)
C1
Pressure is above 980 with speeds
between 74-95 mph, and storm
surges up to 1.5 m (Minimal Damage)
C2
Pressure is between 979-965 with
speeds between 96-110 mph, and storm
surges up to 2.5 m (Moderate Damage)
C3
Pressure is between 964-945 with
speeds between 111-130 mph, and storm
surges up to 3.7 m (Extensive Damage)
C4
Pressure is between 944-920 with
speeds between 131-155 mph, and storm
surges up to 5.5 m (Extreme Damage)
C5
Pressure is below 920 with speeds of
156 mph or more, and storm surges up
to 5.5 m (Catastrophic Damage)
Tornadoes
(Fujita Scale)
F0
65-85 mph
Weak tornado
86-110 mph
F1 Moderate tornado
111-135 mph
F2 Strong tornado
136-165 mph
F3 Significant tornado
F4
166-200 mph
Devastating tornado
Over 200 mph
F5 Devastating/Violent tornado
Tornadoes
•A dark funnel of strong winds that spiral
upward, they can reach speed of 500 KPH
•Can start as a funnel cloud that reaches the
Earth’s surface.
•Air pressure inside the tornadoes funnel is
much lower than the air pressure outside
which make it act like a huge vacuum cleaner.
•The region in the U.S. where most tornadoes
occur is called Tornado Alley (central U.S.)
Parts of a tornado
Funnel cloud
vortex
Becomes tornado once it reaches the ground
How Do Tornadoes Form?
#1 –two different fronts meet and create a rotating spiral
in the atmosphere
#2 – these winds form a horizontal rotation
then updrafts to a vertical rotation
that
#3 – these rotation continues to move faster creating a
tornado
 noaa tornado info.
Tornadoes vs. Water Spouts
 form during the early stages
 weak tornadoes that form
of rapidly developing
thunderstorms and forms on
ground.
 may appear nearly
transparent until dust and
debris are picked up.
 Occasionally, two or more
tornadoes may occur at the
same time.
over warm water.
 common along the Gulf
Coast and southeastern
states.
 occasionally move inland
becoming tornadoes
causing damage and
injuries.
Staying Safe in a Tornado
 Major dangers:
 Powerful/Unexpected winds
 Tips to staying safe:
 Find shelter in a basement or a tornado cellar
 Stay clear of outside walls, windows, and doors
 Get away from cars, mobile homes, and other
objects that might be flipped over or thrown by
winds
 If you are outdoors, find shelter in a ditch or
cave
 Cover your head with your arms