Natural Hazards and Disasters

Natural Hazard  A natural hazards are aspects of the physical world that have a potential to be dangerous to people  A natural hazard is a disaster waiting to happen.  Examples New Orleans is below sea level

Natural Disaster  Occurs when a hazard is activated.  Examples include dormant volcanoes that become active.

Irony  Disasters tend to occur more frequently in highly populated areas.  This is a result of people needing access to water and the coast.  They need to be linked to other markets by the oceans.  Coastal areas are usually where tectonic plates exist.

Evaluating by Grid System  Used to create a profile of a disaster.  Measured using the following components  Frequency  Duration  Areal Extent  Speed of onset  Spatial dispersion  Temporal Spacing

Frequency  How often an event might happen.  Example: greater chance of a blizzard in Newfoundland than Egypt  This will affect the way people handle and prepare for a disaster.

Duration  Length of time the disaster exists  Earthquakes have a short duration  Droughts can last months  Badger Newfoundland

Badger NF Bad 

Badger NF Really Bad

Extent  Disaster can affect large or small areas.  Tornados usually affect a small area  Hurricanes can travel long distances and affect a wide area.

Spatial dispersion  This is the likelihood of a disaster affecting an area.  Areas below sea level are more likely to flood  Areas located around warmer waters and bays increase the strength of storms.

Temporal Spacing  This refers to how predictable the occurances of the disaster is.  Hurricane season occurs around the same time each year between June 1 – Nov.30  Earthquakes are random and can happen any time

Atmospheric Hazards  Storms occur when opposite air masses collide rapidly forming winds and precipitation. This is called a storm front.  The severity is determined by the differences between the two air masses.  When a very cold air mass collides with a very hot, a greater storm will occur.

Tropical Cyclones  These occur in equatorial regions.  They originate over the ocean and move by the prevailing winds.  They gain intensity as they travel over warm and cold waters.  These are also known as hurricanes, typhoons in Asia

Tornadoes  Tornadoes originate over land  Triggered when warm humid air is forced to rise over cold drier air  The result is a twisted storm with winds blowing in opposite directions forming a cone shape  Tornado winds can move up to 500 km/hr

Floods  Floods occur usually in populations that are close to rivers or lakes  Happen in spring when there is an increase in melting and precipitation  Also occur from ocean surges on coastal areas.

Drought  Droughts occur in the hot summer months when there is little or no rainfall  This disaster has claimed the most lives and occurs in the poorer areas of the world  The Sahel in Sub Saharan Africa

Biological Hazards  These are disease outbreaks that affect millions of people and can last many years  Have disastrous affects on LDCs that cannot afford vaccines, medications, and disease prevention education.  2.2 million people die a year from measles and malaria even though we have a cure

 80% of all diseases in the LDCs are a result of a lack of clean drinking water.  Diseases are also spread through mosquitoes.  This is particularly harmful since most LDCs cannot afford basic mosquito nets or techniques to kill mosquitoes

Geological Hazards  Earthquakes  Most violent and sudden of geological hazards  Occurs when tectonic plates collide  Particularly devastating in LDCs because they are highly populated  Also do not have well built structures of infrastructure

Volcanoes  Volcanoes are generally not as destructive as the other disasters  They are usually predictable and allow for evacuation when there are funds available  LDCs that cannot afford evacuation are particular susceptible

Slides and Avalanches  This occurs when snow, mud, or debris slide down a slope of a mountain.  Usually are a result of a triggering event like an earthquake or heavy rainfall  Removal of vegetation also affects this.

Tsunamis  These originate in the ocean and travel to coastal areas.  Usually caused by earthquakes in the ocean which creates a giant wave that reaches the coastal areas  Tsunamis happen quickly  LDCs do not have the ability to monitor and prepare these events.