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Between 1980 and 2008, 601 natural disasters have affected the United States and have killed an average of 415 people each year. Natural disasters cause devastation, but they also pique curiosity and interest the minute they touch land. A natural disaster is best defined as a consequence, or a result, of a natural hazard that has disastrous, or negative effects, on animals, humans, and the affected environment. Some natural disasters are caused by climatic condition changes while others are geological.
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A hurricane is best described as strong winds caused by an oceanic low-pressure area that eventually results in thunderstorms and heavy rainfall. Hurricanes are officially deemed hurricanes once they reach sustained winds that are a minimum of 74 miles per hour. They form over ocean waters that are warm, typically beginning as a storm, and as they make their way west, tropic warm waters fuel them. As moist, warm air makes its way to the storm's center and spirals upwards, torrential rains are released. As more water vapor is sucked up by the updrafts, a cycle is triggered that strengthens this storm and a hurricane can only be stopped by making contact with cooler water or land. A hurricane named Florida Keys became the most intense hurricane in United States history when it hit landfall. This hurricane hit in 1935 and was a category five hurricane. At category five, this hurricane produced winds of more than 155 miles per hour. The deadliest hurricane in United States history hit in 1900 in Galveston, Texas and killed 8,000 people.
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A tornado is a natural disaster that when north of the equator, spins in an anti-clockwise direction, and when south of the equator, spins in a clockwise direction. A tornado is a violent, strong wind caused by threatening weather conditions that spins faster than 450 kilometers per hour. Once this column of air touches ground, it causes great devastation to everything in its path. Large thunderstorms spawn tornadoes. Winds from a tornado can reach 300 miles per hour. Each year, the United States is affected by approximately 800 to 1,200 tornadoes, with a great majority of these striking Tornado Alley, an area stretching across Kansas and Oklahoma from northwest Texas. The most powerful tornado to ever hit Earth occurred in the United States in 1999 and hit Oklahoma. This F5 tornado produced winds of 318 miles per hour, leveled neighborhoods, and left 36 people dead.
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An avalanche is a natural disaster that occurs when large snowballs tumble down the sides of mountains and shatter. These are most common following a heavy snowfall. Avalanches move quickly down mountainsides and occur due to several factors, such as temperature, loud noise, wind, storminess, and slope steepness. Avalanches kill about 150 people every year with fatalities rising since the 1950s. The United States is fifth in avalanche occurrence, with most avalanches occurring in Alaska, Colorado, and Utah. Internationally, most avalanches and avalanche-related deaths occur in Austria, Switzerland, the Alpine countries of France, and Italy. In the United States, most avalanches happen during January, February, and March, claiming an average of 17 lives.
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A blizzard is simply defined as a severe winter storm. The combination of heavy snowfall, strong winds, and low temperatures are the characteristics of a blizzard. In the northeastern United States in 1888, a blizzard took the lives of 400 and is now known as the Great Blizzard of 1888. Two ships were also wrecked during this storm.
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A drought is a natural disaster in which a geographic region is experiencing an abnormally dry climate due to a low yearly rainfall. Droughts cause crop damage, water shortage, and death to animals and humans. Forest fires also increase during droughts. A drought can be hydrological or meteorological. Between 1980 and 2008, about 410 droughts occurred resulting in 558,565 people killed and more than one billion people affected. Every year an average of 19,261 people lose their lives to drought with India being most often affected.
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A flood occurs when dams and rivers overflow resulting in the nearby land becoming submerged. Water-borne diseases can spread, water can become contaminated and scarce, food shortages can occur, food prices can rise, neighborhoods can be destroyed, and people and animals can die. The most common natural disaster throughout the world is a flood, with 40 percent of all natural disasters being floods. Between 1998 and 2008, 2,887 floods have occurred, resulting in 195,843 lives lost. On average, 6,753 people lose their lives each year due to flooding. The deadliest flood recorded in history was the Great Flood of 1931. This flood hit China and affected this country during the winter, spring, and summer during that particular year. Three rivers, the Yellow, Yangtze, and Huai rivers, all flooded together. The Great Flood of 1931 took somewhere between 3.7 and 4 million lives due to starvation or drowning.
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It is estimated that millions of earthquakes rock the Earth each year, but many are not detected due to small magnitude or because they hit areas that are remote. Earthquakes occur when tectonic plates slide against or collide against each other. Earthquakes occur in fault zones. When tectonic plates collide, seismic waves (massive vibrations) are sent due to stress being released. The Richter scale is used to measure an earthquake's magnitude. So far in 2010, 6,838 earthquakes have occurred and 4,264 occurred during 2009 in the United States. Worldwide, 16,945 earthquakes have so far occurred this year, while 14,808 occurred in 2009. The 1960 Chile Earthquake was the biggest earthquake to ever be recorded. This earthquake killed nearly 6,000 people and leveled neighborhoods. This earthquake measured 9.5 on the Richter scale, which led to waves measuring 35 feet as far as 6,000 miles away. A nearby active volcano, Cordon Caulle, also was forced to erupt due to this earthquake. Hilo, Hawaii was destroyed as a result as well.
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A tsunami produces waves of 50 feet high or more. This natural disaster is caused by an oceanic volcanic eruption or submarine earthquake which produce a set of tidal waves. Tsunamis are incredibly powerful and dangerous. Their damage can affect regions as far as thousands of miles from the source of the storm. Between 1998 and 2008, 18 tsunamis have occurred, killing 229,551 people. Every year, an average of 7,916 people die due to tsunamis. Sri Lanka, India, and Indonesia are most often affected.
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The most active volcanoes in the world are found in Japan, Indonesia, and the United States. In the United States, up to five volcanoes each year have erupted since 1980. Hawaii and Alaska have the most volcanic eruptions. An eruption occurs when the pressure from the gases inside molten rock become top much. The hazards associated with a volcano include lava, gases, pyroclastic flows, earthquakes, explosive eruptions, and landslides. Worldwide, there are 2,500 active volcanoes. Any living thing around a volcano is at risk. The 1815 Tambora Eruption occurred in south Indonesia on Sumbawa Island. Mt. Tambora erupted for five days and is the most powerful volcanic eruption to be recorded in history, recorded as a seven on the Volcanic Explosivity Index.
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Wildfires, also referred to as forest fires, are natural disasters that result from arson, human carelessness, or volcanic eruptions. Drought can also result in wildfires, as can lightning. These fires endanger every living thing nearby. In 2009, 5,708,150 acres were burned worldwide as a result of wildfires. In 2008, California wildfires claimed 1,339,839 acres.
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Prevention Web. (2010). United States of America: Disaster Statistics. Retrieved on November 10, 2010 from Prevention Web: http://www.preventionweb.net/english/countries/statistics/?cid=185.
Science Daily. (2010). List of Major Natural Disasters in the United States. Retrieved on November 16, 2010 from Science Daily: http://www.sciencedaily.com/articles/l/list_of_major_natural_disasters_in_the_united_states.htm
Abbott, P.L. (2008). Natural Disasters (7th Edition). Boston: McGraw – Hill.
Aguado, E. & Burt, J.E. (2004). Understanding Weather and Climate (3rd Edition). Upper Saddle River, New Jersey: Prentice Hall.
Lutgens, F.K. & Tarbuck, E.J. (2004). The Atmosphere: An Introduction to Meteorology (9thEdition). Upper Saddle River, New Jersey: Prentice Hall.
Ackerman, S.A. & Knox, J.A. (2006). Meteorology: Understanding the Atmosphere (2nd Edition). California: Brooks Cole.