Air related disasters
Cloudburst and air
Cyclone is a region of low atmospheric pressure
surrounded by high atmospheric pressure resulting
in swirling atmospheric disturbance accompanied by
powerful winds blowing in anticlockwise direction in
the Northern Hemisphere and in the clockwise
direction in the Southern Hemisphere
They occur mainly in the tropical and temperate
regions of the world.
Cyclones in India are moderate in nature.
Some of the general characteristics of a
1. Strong winds
2. Exceptional rain
3. Storm surge
Fully mature tropical cyclone is a spiral pattern of
highly turbulent giant cumulus thundercloud
bands. These bands spiral inwards and form a
dense highly active central cloud core which raps
around a relatively calm zone.
This is called the “eye” of a cyclone.
The eye looks like a black hole or a dot
surrounded by thick clouds. The outer
circumference of the thick cloud is called the „eye
Cyclones are known by different names
in different parts of the world
¨Typhoons in the Northwest Pacific Ocean west of the
¨Hurricanes in the North Atlantic Ocean, the
Northeast Pacific Ocean east of the dateline, or the
South Pacific Ocean.
¨Tropical cyclones - the Southwest Pacific Ocean and
Southeast Indian Ocean.
¨ Severe cyclonic storm” (the North Indian
¨ Tropical cyclone (the Southwest Indian
¨ Willie-Willie in Australia
¨ Tornado in South America
Fig .Orissa Super
29th October 1999, Super-
cyclone with wind speed of
260-300 km/hour hit the 140
km coast of Orissa with a
storm surge created in the
Bay-of-Bengal with water
level 9 metres higher than
Within a period of 36 hrs
ravaged more than 200 lakh
hectares of land, devouring
trees and vegetation, leaving
behind a huge trail of
The violent cyclone was
broke the backbone of
Orissa’s economy and killed
Cyclones vary in frequency in various parts of the world
The 7516.6 km long Indian coastline is the earth‟s most
cyclone battered stretch of the world. Around 8 per cent of
the total land area in India is prone to cyclones.
About two-third of the cyclones that occur in the Indian
coastline occur in the Bay of Bengal.
The states which are generally affected in the east coast are
West-Bengal, Orissa, Andhra Pradesh; Tamil Nadu and on
the west coast Gujarat, Maharashtra, Goa, Karnataka and
Death associate with noteworthy Tropical
Cyclones (1970 – 2005)
A tornado is a violently rotating column of air extending
from a thunderstorm to the ground
Change in wind direction
Increase in wind speed
Rising air within a thunderstorm
A lower cloud base in the center of the
photograph identifies an area of
rotation known as a rotating wall
cloud. This area is often nearly rain-
free. Note rain in the background.
Moments later a strong tornado
develops in this area. Softball-
size hail and damaging
"straight-line" winds can occur
with this storm.
Look out for:
•Dark, often greenish
•Loud roar; similar to a
Where is the safest place to go
during a tornado?
Basement Ditch Shower Inner Hallway Center of Room
During a Tornado
Violent cyclonic storm that develops in the
Wind speeds are > 74 mph
Rotation and Pressure
In which direction does a hurricane rotate?
Is the barometric pressure inside the hurricane
high or low?
When is Hurricane Season?
What is the role of the National Weather
Service during hurricane season?
Provides weather information, such as data
Responsible for issuing watches and warnings
to the media and general public
Watch vs. Warning
What is the difference between a Hurricane
Watch and a Hurricane Warning?
Watch – Tropical storm poses a threat to coastal
areas with 36 hours
Warning - Tropical storm conditions are expected
in a coastal area within 24 hours
What conditions must be present for a
hurricane to develop?
Warm ocean temperatures
(>80˚ F) up to 60m deep
Little to no wind shear
Low pressure system at least 5˚
North or South of Equator
Rotation caused by winds
What is the major source of energy
fueling a hurricane?
Heat Energy evaporating from the ocean
Shower and thunderstorm
moves over closed circulation,
winds greater than 39 mph
Eye is developed, winds > 74
By what two factors is hurricane
What is the Scale Used to Categorize
Category Max Wind Speed
Storm Surge m
1 74-96 > 980 1-1.7 (3-5)
2 97-111 979-965 1.8-2.6 (6-8)
3 112-131 964-945 2.7-3.8 (9-12)
4 132-155 944-920 3.9-5.6 (13-18)
5 > 155 < 920 > 5.7 (>19)
What causes the damage in a hurricane?
How has a hurricane affected you
Damage to your house from wind?
Damage from flooding?
Destroyed vacation house?
Damage to family members’ homes?
A cloudburst is an extreme amount of
precipitation, sometimes with hail and thunder,
which normally lasts no longer than a few
minutes but is capable of creating flood
Manali Cloud Burst Bridge
The cloud burst in India occurs during
monsoon season over the orographically
dominant regions like Himalayan region,
North-Eastern states and the Western
The associated convective cloud can extend
up to a height of 15 km above the ground.
Cloudbursts are associated with intensive heating of air
masses, its rapid rising, and formation of thunderclouds.
Interaction with local topography results in upward
motion, especially where the atmospheric flow is
perpendicular to topographic features
July 26, 2005 deluge, the dreadful memories of “Black Tuesday” return to
haunt the mind as soon as a few heavy showers hit the city. The rain
pounded the city ruthlessly that day inundating it with 944 mm of rainfall
and killing over 450 people.
Air Traffic Growth
The air traffic has amazingly increased between the
beginning of aviation and 2001.
But after the World Trade Center attack, many
airlines were in financial difficulty, and the air traffic
started to decrease.
Two years later, the growth came back.
September 11 terror attacks
JAL Flight 123
Other crashes with high death tolls
The probable cause of airplane accidents
Three key stages of activities that are taken up within disaster risk management are-
1. Before a disaster (pre-disaster) 2. During a disaster (disaster occurrence). 3. After
a disaster (post-disaster)