STORMS
• Hurricane
– A low-pressure tropical storm that
develops in the North Atlantic and
Eastern North Pacific
• Tornado
– One of the smallest, yet most violent,
storm types
• Thunderstorm
– Disturbance caused by cold front,
thunder and lightning occur
HURRICANE
• Form over ocean
between 5 & 15º N & S
of the equator
• Counter- clockwise spin
• Winds must be over 74
mph; storm surge
• Named alphabetically
with alternating male
and female names
• Move 3-25 mph; 600
miles wide
Origin of the word hurricane
• The word hurricane is derived
from the name of a native
Caribbean Amerindian storm
god, Huracan, via Spanish
huracán.
• Huracan: Mayan god of wind,
storm, and fire
The Names of Hurricanes
• 1953, Atlantic tropical storms have been named
from lists originated by the National Hurricane
Center.
• Now maintained & updated by an international
committee of the World Meteorological
Organization
• Original name lists featured only women's names.
• In 1979, men's names were introduced
•
Six lists are used in rotation. Thus, the 2005 list
will be used again in 2011.
Hurricane Names for 2007 & 2008
2007
2008
Andrea
Barry
Chantal
Dean
Erin
Felix
Gabrielle
Humberto
Ingrid
Jerry
Karen
Lorenzo
Melissa
Noel
Olga
Pablo
Rebekah
Sebastien
Tanya
Van
Wendy
Arthur
Bertha
Cristobal
Dolly
Edouard
Fay
Gustav
Hanna
Ike
Josephine
Kyle
Laura
Marco
Nana
Omar
Paloma
Rene
Sally
Teddy
Vicky
Wilfred
Hurricane Formation
Hurricane Symbol
Satellite Images of
Hurricanes: Andrew
Hurricane Hugo
Hurricane Ivan
Hurricane Katrina
The Saffir-Simpson Scale
• Tropical Storm
Winds 39-73 mph
• Category 1 Hurricane — winds 74-95 mph
• No real damage to buildings. Damage to unanchored
mobile homes. Some damage to poorly constructed
signs. Also, some coastal flooding and minor pier
damage.
- Examples: Irene 1999 and Allison 1995
Category 2 Hurricane — winds 96-110 mph
Some damage to building roofs, doors and
windows.
Considerable damage to mobile homes.
Flooding damages piers and small craft in
unprotected moorings may break their
moorings.
Some trees blown down.
- Examples: Bonnie 1998, Georges (FL & LA) 1998
and Gloria 1985
• Category 3 Hurricane — winds 111-130 mph
– Some structural damage to small residences and
utility buildings. Large trees blown down. Mobile
homes and poorly built signs destroyed. Flooding
near the coast destroys smaller structures with
larger structures damaged by floating debris.
Terrain may be flooded well inland.
- Examples: Keith 2000, Fran 1996, Opal
1995, Alicia 1983 and Betsy 1965
Category 4 Hurricane — winds 131-155
mph
More extensive curtain wall failures
with some complete roof structure
failure on small residences.
Major erosion of beach areas. Terrain
may beflooded well inland.
- Examples: Hugo 1989 and Donna 1960
• Category 5 Hurricane — winds 156 mph and
up
Complete roof failure on many residences
and industrial buildings. Some complete
building failures with small utility buildings
blown over or away. Flooding causes major
damage to lower floors of all structures near
the shoreline. Massive evacuation of
residential areas may be required.
- Examples: Katrina, 2005; Andrew(FL) 1992,
Camille 1969 & Labor Day 1935
Rate that hurricane:
• It has wind speeds of 76 mph.
What category is it?
• This storm has wind speeds of
105 mph. What category is it?
• A hurricane with winds of 125
mph. What category is it?
Rate that hurricane:
• It has wind speeds of 134 mph.
What category is it?
• This storm has wind speeds of
154 mph. What category is it?
• A hurricane with winds of
175mph. What category is it?
TORNADO
• Spiraling funnel
cloud
• Form along cold
fronts
• Very unpredictable
• Winds can exceed
500 mph inside
tornado
• Mostly occur in
spring
Rating Tornados
• The Fujita Scale is used to rate the
intensity of a tornado by examining
the damage caused by the tornado
after it has passed over a man-made
structure.
• Named for the Japanese scientist Dr.
Ted Fujita that established the scale
in 1971 at the University of Chicago.
• Fujita Tornado Damage Scale
SCALEWIND ESTIMATE *** (MPH)TYPICAL DAMAGE
• F0: 40-72 mph: Light damage. Some damage to chimneys;
branches broken off trees; shallow-rooted trees pushed over;
sign boards damaged.
• F1: 73-112 mph: Moderate damage. Peels surface off roofs;
mobile homes pushed off foundations or overturned;
moving autos blown off roads.
• F2: 113-157 mph: Considerable damage. Roofs torn off
frame houses; mobile homes demolished; boxcars
overturned; large trees snapped or uprooted; light-object
missiles generated; cars lifted off ground.
Fujita Tornado Damage Scale
• F3: 158-206 mph: Severe damage. Roofs and some walls
torn off well-constructed houses; trains overturned; most
trees in forest uprooted; heavy cars lifted off the ground
and thrown.
• F4: 207-260 mph: Devastating damage. Well-constructed
houses leveled; structures with weak foundations blown
away some distance; cars thrown and large missiles
generated.
• F5: 261-318 mph: Incredible damage. Strong frame houses
leveled off foundations and swept away; automobile-sized
missiles fly through the air in excess of 100 meters (109
yds); trees debarked; incredible phenomena will occur.
Fujita Tornado Damage Scale
• *** IMPORTANT NOTE ABOUT FSCALE WINDS: Do not use F-scale
winds literally. These precise wind
speed numbers are actually guesses
and have never been scientifically
verified. Different wind speeds may
cause similar-looking damage from
place to place -- even from building
to building.
Rate that tornado
• It has winds of 65 mph, what does it
rate on the Fujita Scale?
• It has winds of 98 mph, what does it
rate on the Fujita Scale?
• It has winds of 135 mph, what does
it rate on the Fujita Scale?
• It has winds of 175 mph, what does
it rate on the Fujita Scale?
Rate that tornado
• It has winds of 199 mph, what does
it rate on the Fujita Scale?
• It has winds of 212 mph, what does
it rate on the Fujita Scale?
• It has winds of 245 mph, what does
it rate on the Fujita Scale?
• It has winds of 315 mph, what does
it rate on the Fujita Scale?
THUNDERSTORM
• Caused by a
cold front
• Strong winds,
hail, lightning,
heavy rain,
possible
tornadic activity
& flooding
• Are usually over
quickly
Lightning
• Lightning
is a large
electrical
discharge
that
occurs
between
two
oppositely
charged
surfaces.
Lightning Facts
• Lightning can heat the air to
33,000ºC, more than 5 times the
temperature of the sun’s
surface.
• It has an average of 50,000
volts of electricity.
What Can Lightning Tell You
About the Weather?
• The color of lightning can
indicate atmospheric
conditions.
•
Blue = hail
•
Red = rain
•
Yellow or orange = dust
•
White = low humidity
When Lightning Hits a Tree
• Trees sometimes
explode when
struck by lightning.
Why?
• Lightning causes
the sap in tree to
vaporize (turn from
a liquid to gas).
• The steam expands
rapidly as it is
heated, causing
the tree to explode.
Bibliography: Many thanks to
these great resources
•
http://www.tornadoproject.com/fujitascale/fscale.htm
•
http://www.nhc.noaa.gov/HAW2/english/basics/saffir_simpson.shtml
•
http://skydiary.com/kids/lightning.html
•
http://www.geocities.com/alc13.geo/pics.htm
•
http://www1.ncdc.noaa.gov/pub/data/images/hurricane-fran-avhrr10.gif
•
http://schoolweb.missouri.edu/arcadia.k12.mo.us/petsel/page21/pptconnect.html
•
http://www.corriere.it/Media/Foto/2003/01_Gennaio/27/TORNADO.jpg
•
http://www.nhc.noaa.gov/aboutnames.shtml
•
http://en.wikipedia.org/wiki/Huracan
•
http://earthobservatory.nasa.gov/NaturalHazards/Archive/Sep2005/katrina_trmm_23-31aug05_lrg.jpg
•
http://www.abama.com/posters/z7a21h--.htm
•
http://www.weatherwizkids.com/hurricane1.htm
Storm surge
Deep water
Coastline
Shallow water
coastline