Angela+Ward

=.:.Natural Disasters.:. =

==**__Natural disasters occur when a natural hazard affects the environment. It can cause human losses, financi__****__al and environmental losses.__** ==

__**What are hurricanes?**__  __A hurricane is formed when a thunderstorm in the tropical area can grow into a__ __huge, almost massive, hurricane under some certain weather conditions. Several tropic like thunderstorms are able to rotate around a certain area of low air pressure.This is a Tropical depression. If the__ __depression greatly increases so__ __winds reach 39 miles per hour, this is a tropical storm. If wind speeds ar____e increased to more than 74 miles per hour, it's a tropical cyclone,also known as the hurricane. A study found it interesting that out of 608 storms, 50 turned into tropical storms. A storm will increase in strength if there is a supply of warm, moist air to form it. Warm, moisture filled air is found above warm, tropical oceans. Once they are created, hurricanes take the energy from a warm ocean to become increased with strength. While a hurricane stays over warm water it continues to grow in size. A hurricane fades away when it moves from the__ __tropical area. When a hurricane is in high latitudes, where there is cool water, it loses power. When there are no more supplies, moist air by the ocean surface energizes, or feeds, the storm so it shrinks. It weakens by traveling over land too. The spinning of the storm is because of the Coriolis Effect, an item of the Earth's rotation. This causes the air to be drawn into the center of the lowest pressure point to curve. The inside ai__ __r has to go somewhere, so it rises as it circulates. This rising air cools and condenses, creating clouds. Hurricanes don't occur near the equator because there isn't a Coriolis Effect.__

__**How does a tornado from?** __ __A tornado is a violent and whirling wind that extends from a cumulonimbus cloud. Sometimes known as a twister, a tornado has a width of a few__ __meters but can be__ __anywhere from a meter to a kilometer long when touching ground. It can travel from a human step to a kilo__ __meter in length at a time, causing great damage in the process. Tornadoes form when two masses of humidity__ __and__ __temperature differing in heat meet.__

__media type="custom" key="5582597" These are some tornadoes found in the Eastern United States. __

media type="custom" key="5582673" __ **What is a tsunami?** __

__ A tsunami is a series of waves caused by movement under the water. The movement is usually caused by underwater earthquakes. Sometimes, tsunamis are mistaken to be tidal waves, but they are not caused by tidal action at all. To generate ____ a ____ tsunami, the earthquake would most likely be underwater. In deep ____ oceans, tsunamis have very little amplitude (wave height). Wavelengths are up to 1,000 kilometers long, with speeds as fast as a jet liner. __

__ **How do earthquakes form?** Earthquakes form under Earth's surface, two sides of a fault that constantly ____ move, related to one another. This is known as fault slip. The moving of the sides is very rough and is joined by a gradual build-up of energy inside the __ __ rocks along the fault. Eventually, the strain gets a lot of pressure. The fault then ruptures, releasing all the energy that was built up. This energy is released as vibrations known seismic waves. It's actually seismic waves that cause destructive effects that are combined with the earthquakes ____. The location on a fault that the pressure first contrasts at is called the hypocentre, and the position above it on the surface of the Earth is called the epicenter. When the seismic waves reach the surfaces of the earth, they give rise to strong ground, called mountains, causing buildings and other hand-made structures to shake or collapse completely. Earthquakes cause landslides, volcanic eruptions, and even new land mass formations. __

__ **How do forest fires occur?** Forest fires are started by either human causes or nature causes. Natural causes ____are usually started by a zap of light __

__ning, a spontaneous combustion, or a dry ____fuel such as sawdust or leaves. Other cases are by human causes, such as ____<span style="color: #40b540; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;">smoking, recreational, or equipment. There are three elements needed for a forest to ____<span style="color: #40b540; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> burn: heat, oxygen, and fuel. Without these elements, the fire goes out. Occasionally the fire will reach out to a more abundant area of trees. Once the fire enters the combustion stage, it can be three main types of fires: smoldering, flaming combustion, and glowing combustion. A smoldering fire is one that emits smoke but has no flames and isn't self-sustained. A flaming combustion is a fire that has present flames. A glowing combustion is a later stage of a fire and is classified by a slower rate of combustion and blue flame. __

<span style="color: #dd3cd9; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> __<span style="font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> **How do avalanches occur?**

Snow builds up to the point where it cannot support its weight. It then falls ____<span style="color: #dd3cd9; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> down the mountain. An avalanche usually occurs when a person or thing lands on ____<span style="color: #dd3cd9; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> the weakest point of the mountain. Most avalanches begin when heavy snow covers a less dense layer. The bottom ____<span style="color: #dd3cd9; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;">layer of colder snow with more air pocke ____<span style="color: #dd3cd9; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;">t ____<span style="color: #dd3cd9; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;">s is the reason for the dense difference, while the top layer is getting warmer and melting. When snow blows, it can form areas of snow hanging over the edge of a mountain. When something heavy moves the snow, the weak layer gives out, and top layer falls. __

<span style="font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> __**How do volcanoes form and erupt?**__ <span style="color: #2323e1; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> __Volcanoes form usually when two tectonic plates push against each other, causing__ <span style="color: #2323e1; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> __friction in the surface. The plates then push the ground up, forming a volcano. Volcanoes erupt when the build-up of magma and ash suddenly becomes too unbearable and the volcano spews, creating a stream of extremely hot lava running down the volcano sides and exploding from the top. After an explosion,__ __the volcano then waits for the lava to dry, creating more mountainous area for the volcano. Never get near a volcano after it erupts...the lava's temperature gets up to a range of 1300-2400 degrees Fahrenheit!__

<span style="color: #c2b4f8; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;">__**How are floods caused?**__

<span style="color: #800080; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;">__Floods are usually caused by a huge down pour. If there is a thunderstorm, then that also causes a flood, along with tornadoes. Floods are common around places that are moist and lush. They occur when a huge amount of rain pours down for a long period of time. The ground and drains get so full that they overflow and water spews into the streets and other areas.__

<span style="font-family: 'Lucida Console',Monaco,monospace;"><span style="color: #06180e; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;"> __**How do droughts occur?**__ <span style="color: #f0b714; font-family: 'Lucida Console',Monaco,monospace; font-size: 150%;">__ Droughts are changes in the weather where there is very little rain or snow for a long period of time and there is also very little food. A drought is when an area has less than 0.25 millimeters of rain, storms, etc. for over 15 days. Droughts aren't normally known as disasters. They are just normal areas where extremely hot, sunny weather occurs. They are only classified as disasters when they last for long periods of time, and when a numerous amount of people are effected. __

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