Transcript Document

HURRICANES – NATURE’S FURY!!!
Check these out…
You’d probably want to evacuate at
this point…
What kind of damage are we talkin’ about here?
Might want to take the detour…
Ok, So What Exactly Is a Hurricane?
A hurricane can best be
described as a huge
tropical storm (up to 600
miles in diameter)!
Winds can be up to 200
mph!
Storm usually doesn’t last
for more than 7-10 days.
It moves across the ocean
at around 10-20 mph…not
too fast really!
Arrows indicate
“feeder bands”
or “rain bands”
The winds are the strongest around the eye
wall. The eye of the storm is usually about
20 miles in diameter. Within the eye, winds
are calm and the weather is great.
Strongest winds are on the right side,
heaviest rain is usually on the left side.
Rotation and Pressure
In which direction does a hurricane rotate?
COUNTERCLOCKWISE
Is the barometric pressure inside the hurricane
high or low?
LOW
Scary…so when do I need to watch out for these things??
Since we’re in the USA, we’ll focus on what meteorologists call the “Atlantic Basin”.
The Atlantic basin includes the Atlantic Ocean, Caribbean Sea, and the Gulf of
Mexico.
The “hurricane
season” is just a
name for the time
period when we
expect to see
tropical systems
develop. The
hurricane season
for the Atlantic
runs from June 1st
– November 30th.
Peak season is the middle part of September…why
do you think this is?
So where are these “Atlantic Basin” Hurricanes forming???
Storms of the Atlantic
basin will begin forming
in one of three places:
• Off the coast of Africa
• In the Caribbean Sea
• In the Gulf of Mexico
What is the
ITCZ????
Intertropical Convergence Zone
The ITCZ is an
area of low
pressure located
roughly 5 degrees
North and South
of the Equator. It
is a place where
air converges,
rises, and
condenses
(forming clouds).
It is the rainiest
place on Earth!
So What Does a Hurricane Need in Order to Develop?
So a hurricane needs warm water, time to grow, and favorable upper
level winds in the troposphere. If the winds are too strong, they will
blow the hurricane apart – we call that “wind shear!”
Evolution of Hurricane Development -- Stages
Stage 1 – Tropical Wave (Depression)
Usually has begun its life off of the west coast of Africa in the ITCZ.
Tropical depressions have winds of less than 39mph, and are not given a
name.
Lacks structure – no
well-developed
feeder bands or eye
What is the role
Hurricane
Whatofisthe
theNational
role of the
National
Center Weather
(NOAA)?Service
during hurricane season?
• Provides weather information, such
as data from satellites
• Responsible for issuing watches
and warnings to the media and
general public
Evolution of Hurricane Development -- Stages
Stage 2 – Tropical Storm
At this point, the tropical storm is beginning to develop some serious
structure. Winds range from 40-73 mph. In the Atlantic, storms are given
a name when they reach this stage.
Feeder bands are
beginning to develop
– you can see the
center of the low
pressure system
more easily. Eye and
eye wall still are not
well formed.
Evolution of Hurricane Development -- Stages
Stage 3 – Category 1 Hurricane
Winds range from 75-94 mph.
Well-developed
feeder bands. An
eye begins to form
(although it is
covered in clouds).
Storm is tightening
around center.
Evolution of Hurricane Development -- Stages
Stage 4 – Category 2 Hurricane
Winds range from 95-110 mph.
Well-developed
feeder bands. An
eye and eye wall are
usually very well
formed. Storm
continues to tighten
around center.
Evolution of Hurricane Development -- Stages
Stage 5 – Category 3 Hurricane
Winds range from 111-130 mph.
Now considered a
“Major Storm”.
Intense flooding and
building damage will
occur to most areas
on the coast. Further
inland, the damage
will still be
substantial.
Evolution of Hurricane Development -- Stages
Stage 6 – Category 4 Hurricane
Winds range from 131-155 mph.
All shrubs, signs and
trees blown down.
COMPLETE
DESTRUCTION of
mobile homes.
Extensive damage to
doors and windows.
Major damage to lower
floors of structures near
the coast.
Evolution of Hurricane Development -- Stages
Stage 7 – Category 5 Hurricane
Winds greater than 156 mph!
Complete roof failure on
many residential and
industrial buildings.
Some complete building
failures with small
utility buildings blown
over or away.
Massive evacuation of
residential areas on low
ground within 5-10
miles of the coastline
maybe required.
Saffir-Simpson Scale of Hurricane Intensity
Hurricane Naming System – Why do they have names anyway?
•In 1953 the National Weather
Service began naming storms after
women.
•In 1979, men’s names were added
to the list of hurricane names.
• In the Atlantic, there are 6 lists of
names that are recycled.
• In the case of storms so
devastating that reusing the name
is inappropriate, the name is taken
off the list and another name is
used to replace it. The name
“Katrina” is one that will be removed
from the list.
This year’s list
Arlene
Bret
Cindy
Don
Emily
Franklin
Gert
Harvey
Irene
Jose
Katia
Lee
Maria
Nate
Ophelia
Philippe
Rina
Sean
Tammy
Vince
Whitney
More cool stuff to check out…
Aftermath…
Aftermath…
Aftermath…
Aftermath…
Path of Hurricane Irene
What is the difference between a
HurricaneWatch
Watch vs.
andWarning
a Hurricane
Warning?
–Watch – Tropical storm poses a threat
to coastal areas with 36 hours
–Warning - Tropical storm conditions
are expected in a coastal area within 24
hours