NATURAL DISASTER

NATURAL
DISASTER

WHAT IS NATURAL DISASTER

 A natural disaster is a major adverse event resulting from natural processes
of the Earth; examples include floods, hurricanes, tornadoes, volcanic
eruptions, earthquakes, tsunamis, storms, and other geologic processes. A
natural disaster can cause loss of life or damage property and typically
leaves some economic damage in its wake, the severity of which depends
on the affected population's resilience and on the infrastructure available.

 In modern times, the divide between natural, man-made and man-
accelerated is quite difficult to draw with human choices like architecture,
fire, resource management or even climate change potentially playing a
role. An adverse event will not rise to the level of a disaster if it occurs in an
area without vulnerable population. In a vulnerable area, however, such as
Nepal during the 2015 earthquake, an adverse event can have disastrous
consequences and leave lasting damage, which can take years to repair.
The disastrous consequences also impact the mental health of effected
communities often leading to post-traumatic symptoms. These increased
emotional experiences can be supported through collective processing,
leading to resilience and increased community engagement.

WHAT IS

THUNDERSTROM

A thunderstorm, also known as an electrical
storm or a lightning storm, is
a storm characterized by the presence
of lightning and its acoustic effect on the Earth's
atmosphere, known as thunder. Relatively weak
thunderstorms are sometimes
called thundershowers. Thunderstorms occur in
a type of cloud known as a cumulonimbus. They
are usually accompanied by strong winds, and
often produce heavy rain and
sometimes snow, sleet, or hail, but some
thunderstorms produce little precipitation or no
precipitation at all. Thunderstorms may line up in
a series or become a rainband, known as
a squall line. Strong or severe
thunderstorms include some of the most
dangerous weather phenomena, including large
hail, strong winds, and tornadoes. Some of the
most persistent severe thunderstorms, known
as supercells, rotate as do cyclones. While most
thunderstorms move with the mean wind flow
through the layer of the tropospher that they
occupy, vertical wind shear sometimes causes a
deviation in their course at a right angle to the
wind shear direction.

WHAT IS

TORNADO

A tornado is a violently rotating column
of air that is in contact with both the surface
of the Earth and a cumulonimbus cloud or, in
rare cases, the base of a cumulus cloud. The
windstorm is often referred to as
a twister, whirlwind or cyclone, although
the word cyclone is used in meteorology to
name a weather system with a low-pressure
area in the center around which, from an
observer looking down toward the surface of
the earth, winds blow counterclockwise in the
Northern Hemisphere and clockwise in the
Southern. Tornadoes come in many shapes
and sizes, and they are often visible in the
form of a condensation funnel originating
from the base of a cumulonimbus cloud, with
a cloud of rotating debris and dust beneath it.
Most tornadoes have wind speeds less than
110 miles per hour (180 km/h), are about 250
feet (80 m) across, and travel a few miles
(several kilometers) before dissipating.
The most extreme tornadoes can attain wind
speeds of more than 300 miles per hour
(480 km/h), are more than two miles (3 km)
in diameter, and stay on the ground for
dozens of miles (more than 100 km).

HOW DO THUNDERSTROM FORM

 On a hot summer day the surface of the Earth is
heated by the sun. The Earth's surface heats the
air just above the surface through the process of
conduction.

 The action of warm air rising and cold air sinking
(convection) plays a key role in the formation of
severe thunderstorms. If the warm surface air is
forced to rise, it will continue to rise, because it is
less dense than the surrounding air. In addition, it
will transfer heat from the land surface to upper
levels of the atmosphere through the process of
convection.

 Two of the most important ingredients for
thunderstorm formation are instability (unstable
air) and moisture.

There are three main types of thunderstorms;
orographic, air mass, and frontal.

HOW DO TORNADO FORM
The most violent tornadoes come from supercells,
large thunderstorms that have winds already in
rotation. About one in a thousand storms becomes a
supercell, and one in five or six supercells spawns off a
tornado.
Tornadoes can occur at any time of year, but they are
more common during a distinct season that begins in
early spring for the states along the Gulf of Mexico.
The season follows the jet stream—as it swings farther
north, so does tornado activity. May generally has
more tornadoes than any other month, but April's
twisters are sometimes more violent. Farther north,
tornadoes tend to be more common later in summer.