Natural Hazards and Disasters

There are different types of floods, namely flash floods, riverine floods, urban floods, etc. Flash floods can be defined as the floods which occur within six hours of the beginning of heavy rainfall and are usually associated with cloud bursts, storms and cyclones requiring rapid localised warnings and immediate response to reduce damage. Wireless network and telephone connections are used to monitor flood conditions. In case of flash floods, warnings for timely evacuation may not always be possible.

Oil spill is classified under 'Chemical, industrial or nuclear hazards'.

Natural hazards are hazards which are caused because of natural phenomena (hazards with meteorological, geological or even biological origin). Examples of natural hazards are cyclones, tsunamis, earthquake and volcanic eruption which are exclusively of natural origin. Landslides, floods, drought, fires are socio-natural hazards since their causes are both natural and man made. For example flooding may be caused because of heavy rains, landslide or blocking of drains with human waste.

Willy-willy, most commonly known today as dust devils, is an upward spiralling, dust filled vortex of air that may vary in height from a few feet to over 1,000. They are usually several metres in diameter at the base, then narrowing for a short distance before expanding again. They mainly occur in desert and semi-arid areas, where the ground is dry and high surface temperatures produce strong updrafts.

Correct Answer: landslides

The Gulf of Mexico region is known for experiencing tornadoes, particularly during spring months when warm, moist air from the Gulf collides with cold continental air. Willy-willy is a term used in Australia for tropical cyclones, while cyclone is a general term and typhoon specifically refers to Northwest Pacific storms.

They noticed the animals behaving in a different manner. They guessed some danger. So they moved away to a safer part.

The Saffir–Simpson Hurricane Wind Scale (SSHWS) or the Saffir–Simpson Hurricane Scale (SSHS) classifies hurricanes, i.e. Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms, into five categories distinguished by the intensities of their sustained winds.

A 'Lahar' is a type of natural disaster closely related to a volcanic eruption.

The World Conference on Disaster Reduction is a United Nations conference bringing together government officials, non-governmental experts and other specialists from around the world to discuss the growing trend of people affected by natural disasters. WCDR conference was held in Kobe, Japan from January 18–22, 2005. This conference took on particular poignancy coming almost 10 years to the day after the Great Hanshin earthquake in Kobe and less than a month after the 2004 Indian Ocean earthquake and resulting tsunami.

Hurricane Katrina was the deadliest and most destructive Atlantic hurricane of the 2005 Atlantic hurricane season. It was the costliest natural disaster as well as one of the five deadliest hurricanes in the history of the United States. Hurricane Katrina formed over the Bahamas on August 23, 2005 and crossed southern Florida as a moderate Category 1 hurricane, causing some deaths and flooding there before strengthening rapidly in the Gulf of Mexico. The hurricane strengthened to a Category 5 hurricane over the warm Gulf water, but weakened before making its second landfall.

Flash floods most often occur in normally dry areas that have recently received precipitation but may be seen anywhere downstream from the source of the precipitation, even many miles from the source. In areas on or near volcanoes, flash floods have also occurred after eruptions when glaciers have been melted by the intense heat. Flash flooding can also be caused by extensive rainfall released by hurricanes and other tropical storms as well as the sudden thawing effect of ice dams. Human activities can also cause flash floods to occur. When dams, constructed for hydro-electricity, have failed, large quantity of water can be released and can destroy everything within its path.

In deserts, flash floods can be particularly deadly for several reasons. First, storms in arid regions are infrequent but they can deliver an enormous amount of water in a very short time. Second, these rains often fall on poorly absorbent and often clay-like soil, which greatly increases the amount of runoff that rivers and other water channels have to handle. These regions tend not to have the infrastructure that wetter regions have to divert water from structures and roads, such as storm drains, culverts and retention basins.

On November 25, 1839, an enormous cyclone caused a 40-foot storm surge that hit the ancient city of Coringa in present Andhra Pradesh. The cyclone wiped out the harbour city, destroyed 25,000 ships and vessels in its bay and killed 3,00,000 people. Survivors never entirely rebuilt the city. City of Coringa was known for ship building and repairing. This storm caused the third largest loss of life from any tropical cyclone worldwide, tied with Vietnam’s 1881 Haiphong typhoon (also causing 300,000 fatalities). Storms in the Bay of Bengal actually account for seven of the 10 deadliest hurricanes, typhoons and cyclones recorded in history.

All have the potential to generate a tsunami.