#15 hurricanes
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A powerpoint about Hurricanes and their effects.TRANSCRIPT
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Hurricanes
Lets get our noses off the ground and look back to the skies
Tropical Cyclone- A low pressure storm surrounded by rotating windsy Called Hurricanes in the Atlantic & Eastern
Pacificy Called Typhoons in the Western Pacific and
Asia
Form over warm seawater (25C+) and between ~5 and 20 latitude.
GSC 350Natural Disasters
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Global Wind Patterns
See Ch.10 pg. 265 Wind patterns have relationship to
position onthe globe
Latitudedependant(North/South)
Know this
GSC 350Natural Disasters
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Global Wind Patterns
Recall highs and lows
Equatorial low (0)
Subtropical high (30)
Trade winds (SW)
Westerlies(NE)
GSC 350Natural Disasters
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Global Wind Patterns
Coriolis Effect- Deflection of an object (air mass) in a direction due to rotation (right in the Northernhemisphereand left inthe Southern)
This leads toa shearing directionalityof air masses
GSC 350Natural Disasters
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Hurricanes GSC 350Natural DisastersNorthern Hemisphere Southern Hemisphere
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Hurricanes GSC 350Natural DisastersCounter Clockwise Clockwise
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Hurricanes GSC 350Natural Disasters Form within the trade winds, disperse
within the westerlies
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Hurricanes GSC 350Natural Disasters
Hurricanes contain rising moist warm air rotating into the center (eye)
The Eye is a low pressure zone in the center of the storm where warm wet air rotates around and dry cool air descends into
The eye is calm, butthe strongest windsexist within its walls
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Hurricanes GSC 350Natural Disasters
200km+ wide (diameter), eye ~20km
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Hurricanes GSC 350Natural Disasters
Approaching the eye, wind velocities increase, pressure drops(figure 14-2 pg.417)
Once inside eye, windvelocities are zero
Consider as a stormpasses over you andyou are within theeye, what will happennext?
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Hurricanes GSC 350Natural Disasters
We classify hurricanes based upon wind speed and barometric pressure
Saffir-Simpson Scale- divides hurricanes into 5 categories (1 weakest, 5 strongest)
Category Pressure (mbar) Surge (ft) Wind (mph)
1 >980 4-5 75-95
2 965-979 6-8 96-110
3 945-964 9-12 111-130
4 920-944 13-18 131-155
5 18 >155
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Hurricanes GSC 350Natural Disasters
Damaging products of hurricanes-y Storm Surge- Due to low pressure and high
winds, sea level rises with hurricane
y Wind and Rain- produced by storm, can cause damage and flooding (along with surge)
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Hurricanes GSC 350Natural Disasters
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Hurricane Case Study GSC 350Natural Disasters
Typhoon Haiyan (Yolonda) November 2013y Category 5y Max winds- 195mphy Pressure- 895 mbary Storm surge- 17fty Rainfall- 11in+ (12hr)
Landfall in thePhilippinesNovember 7th
Well defined eye
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GSC 350Natural DisastersHurricane Case Study
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GSC 350Natural Disasters
4,000+ confirmed deaths Estimated damage
~1.1billion USD Philippine warnings
issued prior to stormlandfall
Entire cities destroyed Waves/ storm surge were major culprit in
damage/ loss of life
Hurricane Case Study
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GSC 350Natural Disasters
Aftermath?
Hurricane Case Study
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EXTRA CREDIT GSC 350Natural Disasters
Field trip this Sunday (November 24th)y Meeting 8:00am at San Antonio Damy We will be done by lunch timey Forms to sign on Thursdayy Short 1 page summary due Dec. 5th
Exercise #2 (requires Excel)y Assignment due Dec. 5th
One or the other, will be no more than 5% of your grade
Map
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Next Time GSC 350Natural Disasters
We will skip risk and mitigationy We have touched on these topics throughout the
quarter
Last assignment (Exercise #15)y Review floods
Recurrence intervals (understand how to calculate) Hydrographs (know what you are looking at)
Tamara will lecture on global warming
Midterm Review (Midterm 11/26)
HurricanesHurricanesGlobal Wind PatternsGlobal Wind PatternsGlobal Wind PatternsHurricanesHurricanesHurricanesHurricanesHurricanesHurricanesHurricanesHurricanesHurricanesHurricane Case StudyHurricane Case StudyHurricane Case StudyHurricane Case StudyEXTRA CREDITNext Time