Described in its simplest terms, a tornado is a vertical funnel comprised of rapidly rotating air. A tornado doesn’t appear spontaneously, however. They descend from a certain type of explosive thunderstorm. To understand how a tornado is formed, it’s necessary to examine how the thunderstorms that spawn them are created.
Flood
A flood is an overflow of a body of water that submerges land not normally covered by water. While bodies of water rise with the tides and seasonal rains or snow melts, this is only considered flooding if the water engulfs areas where people live, causing damage or injury. There are several types of floods.
Wildfire
Millions of acres are burned in wildfires every year, according to the United States Fire Administration. In fact, in certain years, more than 96,000 fires have been reported, burning as much as 9,800,000 acres of land. These fires affect all types of landscapes from forest to fields, creating billions of dollars worth of damage,
Lightning
It is reported that 16 million lightning storms occur around the world annually. These bolts of light are usually seen during thunderstorms and combined with the booming sound of thunder. Lightning has been studied by scientists, meteorologists and weather enthusiasts for centuries. Since being studied by Ben Franklin in 1752,
Hurricane
What is a hurricane? A tropical storm system that produces winds with speeds of over 74 mph is called a hurricane. Specifically, a hurricane is a type of tropical storm that normally forms over the Atlantic Ocean or eastern Pacific Ocean. There are other names given to tropical storms that occur in other areas of [...]
Earthquake
An earthquake happens when two sections on the earth suddenly slip past each other. The slip occurs because of a crack or break in the earth. This is called the fault plane. Directly below the fault plane is the epicenter. Below that is the hypocenter, which is where the earthquake originates. Earthquakes are typically associated [...]
Tsunami
The word tsunami became firmly implanted in the world’s lexicon in December 2004, just one day after Christmas. By the end of that day, the Indian Ocean disaster had left over 150,000 people dead and millions more injured and homeless. Eleven countries were directly affected by the destruction and dozens more
Avalanche
Able to sweep trains off their tracks and destroy entire villages, avalanches are a beautiful and potentially fatal natural disaster. Although news reports imply that they can strike without warning, an avalanche often starts as a result of a victim triggering them. Most fatalities from these deadly disasters occur in the winter months.
Volcano
A volcano is a whole in the Earth’s crust that allows the liquid hot magma and gasses that make up the inside of the planet to escape. They get their name from the Roman fire god known as Vulcan. In most cases, volcanoes are made from the moving tectonic plates. These plates are constantly moving [...]
Natural disasters come in many forms, and virtually no place on earth is immune to them. As this overview shows, different types of natural disasters have their own unique characteristics and risks.
Avalanche
An avalanche is a sudden fall of snow down a slope resulting from an outside source of stress on either newly-fallen snow or thawing established snow. Triggering stressors can be natural, such as earthquakes or glacial movement, or man-made, such as explosives or snowmobiles. The risk of avalanche is greatest during the 24 hours after a snowstorm brings a foot or more of fresh snow. At that time, the snow underneath the layer from the storm can become overloaded, and gravity can trigger the avalanche.
Earthquake
Earthquakes, often characterized by sudden, violent shaking of the ground, result from the release of energy within the earth’s crust. Tectonic plate movements near fault lines are often the source of such energy releases. While recent years have seen earthquakes devastate locales from Japan to Haiti, the planet actually experiences hundreds of earthquakes each day, most too weak to be felt. In areas near active fault lines, smaller earthquakes are often a routine part of life.
Flood
Floods occur when rain, dam breakages, or other factors cause a body of water to overflow and submerge normally dry land. Floods can arise quickly, as when intense storms introduce large amounts of water into an area in a short period of time, or slowly, as when runoff from ongoing rains cause a river to crest above its channel. Other natural disasters, such as tsunami or a hurricane’s storm surge, can also cause sometimes catastrophic flooding in coastal areas.
Hurricane
Hurricanes are low pressure systems over tropical or subtropical waters with strong circulating surface winds and heavy storm activity. A hurricane forms when moist atmospheric conditions combine with an existing disturbance near the surface of warm water to form a spinning, organized system fueled by evaporating water. Hurricanes can develop and dissipate entirely at sea, or they can brush past or slam into coastal areas, with effects ranging from heavy storms to devastating wind, rain, and flooding.
Lightning
Lightning is a discharge of electricity from the atmosphere, most commonly -- but not always -- during thunderstorms. While most lightning travels within or between clouds, the most dangerous lightning travels from clouds to the ground in extremely hot strikes that pose severe risks to life and property. Hundreds of people are hurt or killed by lightning strikes every year.
Tornado
A tornado is a violently spinning air column reaching from a thunderstorm cloud to the ground. While tornadoes can form across the world, these natural disasters are usually confined to the United States, particularly the Tornado Alley region of the Central Great Plains. Tornadoes develop in advance of thunderstorms when wind direction changes, wind speed picks up, and a horizontal spinning area develops. Rising air from the thunderstorm’s updraft tilts that spinning area from horizontal to vertical, forming the familiar upright funnel cloud.
Tsunami
A tsunami is a series of waves -- usually in an ocean, but sometimes in a lake -- triggered by an earthquake, landslide, or other event causing a large displacement of water. Tsunami can range in height from a few inches to hundreds of feet, and the 2004 Indian Ocean tsunami, one of the deadliest natural disasters in history, saw waves nearly 100 feet high. While tsunami cannot be predicted with certainty, improvements in seismic monitoring have made possible systems that can often provide early warning when an event triggering a possible tsunami occurs.
Volcano
Volcanoes are ruptures in the planet’s crust where gases, ash, and semi-molten magma vent up to the surface. Volcanoes are usually found where tectonic plates are either pushing together or pulling apart. Active volcanoes pose a risk not only from the immediate explosion, but also, in some cases, from ash and sulfuric acid spewed into the atmosphere. This material can cause volcanic winters, as happened with the eruption of Mt. Pinatubo in 1991, cooling the earth’s temperature for a period of time and in some cases interfering with agricultural production.
Wildfire
Any uncontrolled fire in a wilderness area can be considered a wildfire. Characterized by their large size and the dangerous speed with which they spread, wildfires are particularly hazardous because of their tendency to shift direction without warning. Most wildfires are sparked by natural causes, such as lightning, but man-made wildfires, ignited by cigarettes, campfires, or even arson, also occur.