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Weather Hazards

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On March 18, 1925, the tornado formed in Missouri and traveled 219 ... A violently rotating column of air (vortex) that touches the ground. Tornado Oddities ... – PowerPoint PPT presentation

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Title: Weather Hazards


1
Weather Hazards
  • Tornadoes
  • Hurricanes
  • Droughts
  • Floods

2
A Tornado
3
Deadliest Tornado
  • The Tri-State Tornado is the most violent
    tornado on record
  • On March 18, 1925, the tornado formed in Missouri
    and traveled 219 miles across Illinois into
    Indiana
  • The funnel was up to 0.75 miles across and
    traveled as fast as 73 mph
  • It killed approximately 635 people

4
What is a tornado?
  • A violently rotating column of air (vortex)
    that touches the ground

5
Tornado Oddities
  • Tornados are reported to routinely carry objects
    many miles and have
  • sucked the frogs out of a pond and dropped them
    on a town
  • carried a necktie rack with 10 ties attached 40
    miles
  • carried a flour sack 110 miles from a mill
  • Tornados also drive objects into other objects
    and have
  • driven splinters into an iron fire hydrant
  • driven straw and grass into telephone poles

6
Songer http//www.pitt.edu/super1/lecture/lec0761
/005.htm
7
Where do tornados occur?
  • Tornado Alley covers the Great Plains states

8
Tornado Path
  • View from the air of a tornado path in central
    Oklahoma

9
Waterspouts
  • A waterspout is a tornado that forms over a
    body of water, or a tornado that moves from land
    onto water

10
Dust Devils
  • A dust devil is also a vertical swirling column
    of air
  • They rarely are as strong as even the weakest
    tornadoes

11
Tornado Wind Speed
  • In 1971, Dr. Fujita developed a way of
    measuring the winds of a tornado. He reasoned
    that there was a link between wind speed and the
    damage caused by a tornado. There are 6
    categories of tornados (F0 F5).

12
F0 Category
  • (Weak) winds 40-72 mph, little damage
  • Damage tree branches snapped, chimneys toppled,
    signs torn down

13
F3 Category
  • (Strong) winds 158-206 mph, severe damage
  • Damage most trees uprooted, trains overturned,
    roofs torn off, walls demolished

14
F5 Category
  • (Violent) winds 261- 319 mph, incredible damage,
    rare
  • Damage bark peeled off trees, houses lifted off
    foundations, vehicles travel greater than 100
    yards through the air

15
Tornado Occurrence by Category
16
Tornado Deaths by Category
17
Hurricanes
18
Hurricane Katrina
An interdisciplinary, critical inquiry
19
  • Hurricane Katrina was the costliest and one of
    the deadliest hurricanes in the history of the
    United States
  • It was the sixth strongest Atlantic hurricane
    ever recorded and the third strongest landfalling
    USA hurricane ever recorded

20
Landfall

21
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22
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23
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24
What is a hurricane?
  • A hurricane is an intense, rotating oceanic
    weather system that possesses maximum sustained
    winds exceeding 74 mph

25
In other parts of the world, a hurricane is known
by other names
  • typhoon
  • - in the northeastern Pacific
  • tropical cyclone
  • - in the Indian Ocean and the eastern South
    Pacific

26
How do they form?
  • Hurricanes form and intensify over the ocean
  • They require
  • sea-surface temperatures of at least 80F
  • the influence of the earths rotation to initiate
    a spinning circulation (Coriolis Effect)

27
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28
Most of these systems form between 10 and 30
degrees of the equator and 87 form within 20
degrees of it
29
Storm Surge
  • Definition a rise in sea level along a coastline
    caused by the combination of a hurricane's
    surface winds and the physical geography of a
    coastline

30
Droughts
  • Definition an extended period of below-normal
  • rainfall
  • Although what is considered "normal" varies from
    one region to another, drought is a recurring
    feature of nearly all the world's climatic
    regions

31
Consequences from Drought Conditions
  • Wildfires
  • Desertification
  • Loss of agricultural production
  • Disease
  • Thirst
  • Famine due to lack of water for irrigation
  • Social unrest
  • Migration or relocation of those impacted
  • War for water and foods

32
The Dust Bowl
  • The Dust Bowl was a series of dust storms in
    the central United States and Canada in the mid
    to late 1930s

33
Causes of the Dust Bowl
  • Massive drought
  • Decades of inappropriate farming techniques

34
Results of the Dust Bowl
  • 15 of Oklahomas population migrated
  • USA Government formed the Soil Conservation
    Service

35
Floods
  • A flood is an overflow of water duh?

36
Causes of Flooding
  • The main cause of floods is the location of human
    populations near water
  • The worst floods usually occur when a river
    overflows its banks

37
Preventing Flooding
  • Rivers prone to flooding are often carefully
    managed
  • Defenses such as levees, reservoirs, and weirs
    are used to prevent rivers from bursting their
    banks
  • Coastal flooding has been addressed with sea
    walls and vegetation

38
Levees
39
Reservoirs
40
Weirs
41
Assignment
Create A Pamphlet
42
Weather Hazards of the Earth
  • Cover - must have title and must have some type
    of illustration
  • 1st Section Hurricanes
  • 2nd Section Tornadoes
  • 3rd Section Floods and Drought
  • These areas are to be addressed
  • What is it?
  • What are the effects?
  • What can we do to prepare for it?
  • There must be illustrations
  • Back Cover - your name and the class period
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