Transcript 13.3 Tropical Storms

Tropical Storms
Tropical Cyclone
• Tropical cyclones are large, rotating, lowpressure storms that form over water
during summer and fall in the tropics
• The strongest of these storms in the
Atlantic Ocean are known as hurricanes!
ITCZ
• Intertropical Convergence Zone
Warm tropical waters near the equator…
FORMATION
– Tropical cyclones require two basic
conditions to form:
• An abundant supply of very warm ocean water
• Some sort of disturbance to lift warm air and
keep it rising
Cyclone Movement
• Tropical cyclones move according to the wind
currents that steer them.
Anatomy of Hurricane
What is INSIDE?
– The eyewall is
a band
immediately
surrounding
the eye that
contains the
strongest
winds in a
hurricane.
–Once a
hurricane, the
development
of a calm
center of the
storm, called
an eye, takes
place.
Stages of Tropical Cyclones
1. A disturbance in the ITCZ
zone lifts warm air near
tropical waters
2. Cyclonic winds circle
around a low pressure
center = tropical depression
3. Wind Speeds reach 65
km/hr = Tropical Storm
4. Wind Speeds reach 120
km/hr = Hurricane
Saffir-Simpson Scale
•
Criteria
1. Wind Speed
2. Damage
Level
3. Pressure
4. Storm Surge
Running out of Energy…
– A hurricane will last until it can no longer produce
enough energy to sustain itself. This usually
happens when:
• The storm moves over land and no longer has
access to the warm ocean surface from which
it draws its energy.
• The storm moves over colder water.
Storm Surge
A storm surge occurs when hurricane-force winds drive
a mound of ocean water, sometimes as high as 6 m
above normal sea level, toward coastal areas where it
washes over the land.
Summary
•
Use the following terms in your summary!
1.
2.
3.
4.
5.
ITCZ
Eye & Eyewall
Saffir-Simpson Scale
Storm Surge
“your choice”
Match the following
terms with their
definitions.
___
___
___
___
tropical
depression
hurricane
eyewall
storm surge
A. a tropical cyclone
with wind speeds of
at least 65 km/h
B. the band that has the
highest wind speeds
in a hurricane
C. a tropical cyclone
with wind speeds of
at least 120 km/h
D. a mound of winddriven water that
washes over coastal
lands