Prepared By
Md. Arifuzzaman Arif,
MSc in Disaster Management,
Department of Geography and Environment,
University of Dhaka.
BSc in Forestry & Wood Technology Discipline,
Khulna University.
Spiders by Slidesgo - an introduction to arachnids
Lightning in Bangladesh
1. Prepared By
Md. Arifuzzaman Arif
MSc in Disaster Management
Department of Geography and Environment
University of Dhaka
BSc in Forestry & Wood Technology Discipline
Khulna University
Lightning in Bangladesh
3. What is Lightning?
The occurrence of a natural electrical discharge of very
short duration and high voltage between a cloud and the
ground or within a cloud, accompanied by a bright flash.
Every day 8 million lightning are taking place
somewhere on the earth.
In Bangladesh, Lightning is declared as natural
disaster in 17 May, 2016
4. Lightning Facts
▸ Heat exceeds 50,000 degrees F (3 times
hotter than the surface of the sun)
Lightning strikes earth a 100 times each second
Duration of one stroke of lightning, 1/5th of second.
Lightning can travel at speeds of 60,000 m/sec.
Lightning strokes ranges from 100 m – 8 km length.
Lightning containing an average charge of 30 to 50 lakhs
volts
5. Simply, lightning is the meeting of
negative charges with positive charges
negative charges
positive charges
6. For many years, people used to believe
that lightning is a holy event which is
related to gods that punish those people
who disobey them.
Franklin is the first one who proved that
the lightning is an electric spark
Historical Background
9. Mechanism of Lightning
The lightning occurs in phases
The scientists discovered that the lightning occurs in
two main phases which are the crossing phase and the
returning phase, and they captured photos for these two
phases and said with certainty that the lightning
descends from the cloud and returns again!!
10. Mechanism of Lightning
The first phase
A negative charge descends
from the cloud toward the
ground in part of a second.
The second phase
The positive charge on
the ground meets with
that negative charge.
11. Mechanism of Lightning
The third phase
As a result, a strong electric
spark generates and goes
toward the cloud.
The fourth phase
The returned electric charge and
that is the lightning beam, all of
these four phases happens in 25
Millisecond.
12. Where Does Lightning Strike First
Tall objects such as trees and
skyscrapers are commonly struck
by lightning.
Mountains also make good targets.
The reasons for this is their tops are
closer to the base of the storm cloud.
However, this does not always
mean tall objects will be struck.it all
depends on where the charges
accumulate. Lightning can strike the
ground in open field even if the tree
line is close by.
14. Types of loss resulting from different
types of damage
15. Damage due to lightning
Lightning striking a structure can result in damage to the structure
itself and to its occupants and contents, including failure of
equipment and especially of electrical and electronic systems.
The damages and failures may also extend to the surrounding of
the structure and may even involve the local environment. The
scale of this extension depends on the characteristics of the
structure and on the characteristics of lightning.
A typical lightning stroke is a dramatically powerful natural event
capable of damaging even intentionally protected structures.
It injuries or sometimes even kills animals and people instantly.
16. Damage due to lightning
It can cause fire and shatter
buildings resulting in lot of
destruction and damage.
It can burn trees and also
causes forest fire
23. Safety Measures
Take shelter in a building or car
Do not lie flat on ground
Stay about 15 feet
away from each other
Stay away from all types of water
bodies because water is an
excellent conductor of electricity
24. Safety Measures
Do not take baths and showers
during storms, as water is an
excellent conductor of electricity.
It is safer to use mobile phones and cordless
phones during lightning
25. First aid for Lightning Victims
Administer first aid as
quick as possible
If unconscious: Check
breathing and pulse
Person has a pulse, but
not breathing: Begin
CPR
Check for other
injuries
Most die from heart
attacks/stop breathing
If not CPR qualified:
Call EMS immediately
Keep them calm
Stay with them until
help arrives
26. Lightning Protection System
A lightning conductor is
fixed on the top of tall
buildings to protect them
from damage due to the
lightning
27. Lightning Protection System
The ground wires are placed above the line conductors at such positions
that practically all lightning strokes are intercepted by them (i.e. ground
wires). The ground wires are grounded at each tower or pole through as
low resistance as possible.
Overhead Ground Wires
28. Lightning Protection System
A lightning arrester or a surge diverter is a protective device which
conducts the high voltage surges on the power system to the ground
lightning arrester or Surge diverter
Provide protection for indirect strokes
29. Lightning Protection System
The Earthing Screen
It consists of a network of copper conductors (generally called shield or screen)
mounted all over the electrical equipment in the sub-station or power station.
The shield is properly connected to earth on at least two points through a low
impedance.
On the occurrence of direct stroke on the station, screen provides a low
resistance path by which lightning surges are conducted to ground.
The limitation of
this method is that
it does not provide
protection against
the travelling waves
which may reach
the equipment in
the station.
30. Recommendations
No place outside is safe when thunderstorms are in the area.
If anyone hear thunder, lightning is close enough to strike him or
her.
If anyone hear thunder, immediately move to safe shelter.
Stay in safe shelter at least 30 min after hear the last sound of
thunder.
Planting tall tree such as palm trees in the villages and sub urban
areas.
Creating awareness on the lightning safety by organizing
trainings, seminars etc. in the union level.
Lightning safety guidelines should be included in the children’s
curriculum starting from the primary schools.
Lightning safety measure should be published in the television
radios and dramas.
31. Conclusion
Lightning is common meteorological hazard in Bangladesh
and it is dangerous natural force. Many lightning victims are
caught outside during a storm because they did not act
promptly to get to a safe place. Proper planning and safe
practices can easily increase lightning safety when working
outdoors.
32. Bangladesh disaster-related statistics 2015: Climate change and natural
disaster perspectives.BBS, Statistics and Informatics Division, Ministry of
planning Bangladesh.
BBS,2012: Housing and population census 2011. BBS, Statistics and
Informatics Division, Ministry of planning Bangladesh.
Emergency operation Center-Department of Disaster Management
Bangladesh
Chowdhury M.A.M., and U.K. De,1995: Pre monsoon thunderstorm activities
over Bangladesh from 1983 to 1992.
Martin A Uman, All About Lightning, Courier Dover Publications, 1987.
G V Cooray, Vernon Cooray, The Lightning Flash, IET, 2003.
Richard Kithil, Fundamentals of Lightning Protection, National Lightning
Safety Institute.
Hugh Christian, Steven Goodman, Observing Lightning from Space,
www.nasa.gov, 1998.
The Lightning Process: Keeping in Step, www.noaa.gov, March 9, 2004.
Steve Price, Patrick Barry, Tony Phillips, Where Lightning Strikes,
www.nasa.gov, Dec. 5, 2001.
References
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References