Natural disasters disrupt communities and cause widespread losses that exceed their ability to cope. Disasters result from inappropriately managed risks from hazards and vulnerabilities. Hazards in sparsely populated areas may not cause disasters. Developing countries suffer the greatest costs from disasters, with over 95% of disaster deaths and 20 times greater economic losses as a percentage of GDP than industrialized nations.

1. NATURAL DISASTERS
A disaster is a serious disruption of the functioning of a
community or a society involving widespread human, material,
economic or environmental losses and impacts, which exceeds
the ability of the affected community or society to cope using its
own resources.
In contemporary academia, disasters are seen as the
consequence of inappropriately managed risk. These risks are the
product of a combination of both hazard/s and vulnerability.
Hazards that strike in areas with low vulnerability will never
become disasters, as is the case in uninhabited regions.
Developing countries suffer the greatest costs when a disaster
hits – more than 95 percent of all deaths caused by hazards occur
in developing countries, and losses due to natural hazards are 20
times greater (as a percentage of GDP) in developing countries
than in industrialized countries.

2. A flood is an overflow of water that
submerges land which is usually dry.
The European Union (EU) Floods
Directive defines a flood as a covering
by water of land not normally covered by
water. In the sense of "flowing water",
the word may also be applied to the
inflow of the tide. Flooding may occur as
an overflow of water from water bodies,
such as a river or lake, in which the
water overtops or breaks levees,
resulting in some of that water escaping
its usual boundaries, or it may occur due
to an accumulation of rainwater on
saturated ground in an areal flood. While
the size of a lake or other body of water
will vary with seasonal changes in
precipitation and snow melt, these
changes in size are unlikely to be
considered significant unless they flood
property or drown domestic animals.
A FLOOD CAN CAUSE A
DISASTER

3. LOSS OF FUNCTION OF
STRUCTURES IN FLOODPLAIN
FLOODS
INUNDATION
INTERACTION WITH
HAZARDOUS MATERIALS
STRUCTURE & CONTENTS:
DAMAGED BY WATER
WATER BORNE DISEASES
(HEALTH PROBLEMS)
EROSION AND MUDFLOWS
CONTAMINATION OF GROUND
WATER
CAUSES
OF RISK
DISASTER
LABORATORIES

4. CAUSES OF FLOOD
• Flooding occurs most commonly
from heavy rainfall when natural
watercourses do not have the
capacity to convey excess water.
However, floods are not always
caused by heavy rainfall. They
can result from other phenomena,
particularly in coastal areas where
inundation can be caused by a
storm surge associated with a
tropical cyclone, a tsunami or a
high tide coinciding with higher
than normal river levels. Dam
failure, triggered for example by
an earthquake, will result in
flooding of the downstream area,
even in dry weather conditions.

5. OTHER FACTORS
• Volume, spatial distribution,
intensity and duration of
rainfall over a catchment;
• The capacity of the
watercourse or stream
network to convey runoff;
• Catchment and weather
conditions prior to a rainfall
event;
• Ground cover;
• Topography
• Tidal influences.

6. SUBMITTED BY:- MUSKAN
CLASS 9TH C
ROLL NO 17