2. Bangladesh…
Bangladesh being located on the Tropic of Cancer
receives fairly direct radiation throughout the year
& maintains relatively high temperature. The
country so much disaster prone region
3. Climatic Hazards of
Bangladeh....
There are some Common Natural disaster are…..
Cyclone
Tornados
Nor’Wester
Storm Surges and Tidal Bores
Flood
Coastal erosion
Landslide
Groundwater contamination
Earthquakes
4. Tornado:
A tornado is a violently rotating column of air in contact
with the ground and out from a cumulonimbus cloud.
Tornadoes are capable of inflicting extreme damage.
5. When Tornados Occur……….
• Tornadoes occurs in Bangladesh
during the pre-monsoon hot
season, especially in the month
of April when the temperature is
the highest.
• Anytime of the year- usually in
the spring, summer, and fall
• The most dangerous time for
formation during evening hours
A typical late
afternoon tornado
6. Historical Background:
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 .75 miles across and
traveled as fast as 73 mph.
It killed approximately 635 people.
7. Reasons for Tornadoes Occurrences………
Tornadoes form in unusually violent thunderstorms
when there is sufficient:
(1) instability, and
(2) wind shear present in the lower atmosphere.
Instability refers to warmer and more humid than usual
conditions in the lower atmosphere, and possibly cooler
than usual conditions in the upper atmosphere.
Wind shear in this case refers to the wind direction
changing, and the wind speed increasing with height.
11. Tornado Prone Region in Bangladesh…………….Tornado Prone Region in Bangladesh…………….
In the Bangladesh, the area where the tornadoes
hit the most is called Tornado AlleyTornado Alley. The
District which are in the tornado alley are:
Dhaka
Faridpur
Tangail
Manikgonj
Maymensingh
Gopalgonj
Gaibandha,Rangpur
Brahmmanbaria
Danger!
Danger! Tornadoes!
12. Date: Location: Number of Death:
April 1, 1972 Mymensingh 150
April 17, 1973 Dhaka 681
April 1, 1977 Faridpur 623
April 2, 1977 Gopalgonj, Faridpur 111
April 16, 1978 Mymensingh 150
April 26, 1989 Manikgonj 526
May 13, 1996 Tangail 605
April 14, 2004 Mymensingh &
Netrokona
111
20 March 2005 Gaibandha &
Rangpur
43
4 March 2006 Southern
Bangladesh
4
Table: Individual Tornadoes that killed people in Bangladesh since
independence in 1971
13. Tornadoes Category………..
• Tornadoes can be categorized as "weak",
"strong", and "violent"; with weak
tornadoes often having a thin, rope-like
appearance.
• About 7 in 10 tornadoes are weak, with
rotating wind speeds no greater than about
110 MPH.
• The typical strong tornado often has a
"classic" funnel-shaped cloud associated
with the whirling updraft. Rotating wind
speeds vary from 110 to 200 MPH.
14. Tornado Facts………………….
Tornados can occur almost anywhere in the
world
Duration: a few minutes
Diameter (Avg.): 0.4 km
Length of path (Avg.): 6 km
Funnel can travel from 0 mph up to ~70
mph, usually travels at 30 mph
99% of all tornados in Northern
Hemisphere rotate counterclockwise
15. Deadly Tornado Event in Bangladesh ……..
The Daulatpur Saturia Bangladesh Tornado was an extremely destructive
tornado that occurred in the Manikganj District, Bangladesh on April 26,
1989. It was the costliest and deadliest tornado in Bangladesh's history.
There is great uncertainty about the death toll, but estimates indicate that
it killed around 1,300 people, which would make it the deadliest tornado
in history. The tornado affected the cities of Daulatpur and Saturia the
most, moving east through Daulatpur and eventually northeast and into
Saturia. Previously, the area that the tornado hit had been in a state of
drought for six months, possibly generating tornadic conditions.
16. Deadly Tornado Event in Bangladesh……
• 4 March 2006
• Tornado struck six villages in southern Bangladesh. 4 people killed; 50
injured; 17 seriously injured. Approximately 500 houses were
destroyed, many trees were uprooted and damage occurred to
agricultural crops.
• 20 March 2005
• Tornado swept over Gaibanda and Rangpur district. The devastation
lasted for 5 minutes. Loss of lives were 43 , Injured people 4688 and
damage of houses were 8786.
• 14 April 2004
• Tornado occurred in Mymensing and Netrokona districts in
Bangladesh. It lasted for about 10 minutes. The loss of lives are 66 ,
around 1700 people were injured and 23 villages
• were affected.
17. Most Strong Tornados……..
• All tornados are potentially deadly, but most are
actually relatively weak (74%)…!
• Only 1% of all tornados fall in the F4 – F5 range
18. Consequences …………………
The Effects of Tornadoes on Humans & Nature T can
make People die, can destroy a lot of homes, stores,
and much more and it can make serious injuries.
Damage was extensive over the area, as countless
trees were uprooted and every home within a six
square kilometer area of the tornado's path was
completely destroyed. After the storm hit, an article in
the Bangladesh Observer stated that "The devastation
was so complete, that barring some skeletons of trees,
there were no signs of standing infrastructures".
19. How Tornadoes Impacts the
Environment
Tornadoes could hit hazardous or toxic
materials.
Effects the food chain and disrupts the whole
environment
Destroys topsoil and crops
Food shortages around the surrounding area.
Water contamination,
20. Economic Impacts ……
A tornado is a violent revolving pillar of air pulling
out from a thunderstorm to the ground. Some of the
economic effects of Tornado are that, they can make
people die, can make serious injuries and can
demolish homes and damage properties as well.
21. Tornado risk Reduction………
Tornadoes being Prepared
Turn on your radio or TV to get the latest emergency
information .
A tornado warning is issued should take shelter
immediately.
Make a list of important information and Store
Stored documents in a fire- and water-proof safe
22. During a Tornado………..
The following weather signs may mean that a tornado is approaching:
•A dark or green-colored sky.
•A large, dark, low-lying cloud.
•Large hail.
•A loud roar that sounds like a freight train.
•see a funnel cloud take shelter immediately.
AVOID WINDOWS
Indoor
The safest place in the home is the interior part of a basement.If there is no
basement, go to an inside room or For example bathroom, or closet.
If there is no time to get to a tornado shelter or to a lower level, try to get
under a door frame or get up against something that will support or deflect
falling debris.
Outdoors
Avoid areas with many trees.
Protect your head with an object or with your arms.
•Move away from windows and glass doorways.
23. After a Tornado ……..
Stay indoors until it is safe to come out.
Use a flashlight to inspect your home.
Check for injured or trapped people, without putting yourself in
danger.
Be careful when entering any structure that has been damaged.
Wear sturdy shoes or boots, long sleeves, and gloves when handling
or walking on or near debris.
Be aware of hazards from exposed nails and broken glass.
Do not touch downed power lines or objects in contact with downed
lines.
Report electrical hazards to the police and the utility company.
Use battery-powered lanterns, if possible, rather than candles to light
homes without electrical power.
33. Prepared By-
A.M. Ashraful Alam (216)
Md. Khazem Mahmud (090)
Md. Shahinuzzaman (217)
Abdul Matin Biswas (219)
Md. Jakaria (218)
Md. Nasir Uddin (220)
Mahmudul Hasan (066)
Md. Asaduzzaman (073)
Md. Saiful Islam (029)
Md. Shafiqul Islam (060)
3rd
Year Students
Dept. Of Geography & Environment
University of Dhaka
Date:20.12.13
Editor's Notes
Tornados form from thunderstorms which contain one or more updrafts (upward moving air which is warm and moist). These updrafts form towering cumulonimbus clouds which race upward and cool to form ice crystals (once they reach the anvil of the thunderstorm). Downdrafts of cold air aloft also occur as the thunderstorm intensifies.
Severe thunderstorms, which is an intense thunderstorm with winds of at least 60 mph, most likely produce tornados.
Tornados form from thunderstorms which contain one or more updrafts (upward moving air which is warm and moist). These updrafts form towering cumulonimbus clouds which race upward and cool to form ice crystals (once they reach the anvil of the thunderstorm). Downdrafts of cold air aloft also occur as the thunderstorm intensifies.
Severe thunderstorms, which is an intense thunderstorm with winds of at least 60 mph, most likely produce tornados.
A thunderstorm capable of producing a tornado requires key ingredients such as: warm moist air, cold air aloft, sometime of wind shear(provides vertical motion) and instability high in the atmosphere, and a trigger.
Tornadic thunderstorms usually occur where cold fronts clash with warm fronts over the Southern Great Plains.
Rising updrafts begin to rotate as wind speed changes with direction and height in the thunderstorm. Along the surface of the earth a horizontal rotating column of air is moved vertically to form a shaft which rotates up through the thunderstorm. This area is where most tornados form.
At some point this rotation becomes so intense that a rotating wall cloud descends from the thunderstorm eventually forming a vortex known as a funnel.
This funnel extends downward to the ground where it is officially deemed a tornado
Tornados often are spawned by large thunderstorms known as a mesocylclone
A mesocyclone is a violent thunderstorm in which the entire storm or cell complex is rotating, which gives it a predisposition to produce tornados
Mesocyclonic thunderstorms are also known as “supercells”