The forces that shape the Earth!
Click through the animation to see how tornadoes are formed and how they can impact the surrounding environment.
3. Tornadoes 101
- Tornadoes can occur at any time of the year.
- No terrain is safe from tornadoes.
- Never open windows in severe weather situations. This allows damaging wind and debris to enter the structure.
- 69% of all tornadoes are labeled “weak tornadoes” meaning they have a lifetime of 1-10+ minutes and winds less than 110 mph.
- 29% of all tornadoes are labeled “strong tornadoes” meaning they last 20 minutes or longer and winds reach 110-205 mph.
- 2% of all tornadoes are labeled “violent tornadoes” and can last over an hour.
- Every state has had a tornado, but some states are more prone to them.
- Most tornadoes in the Northern Hemisphere spin counterclockwise, while most tornadoes in the Southern Hemisphere spin clockwise.
- The safest place to be during a tornado is underground, which makes basements and cellars the ideal shelters to get away from tornadoes.
- Most of the world’s destructive tornadoes occur during the the summer in mid-western states of the US.
- Sometimes multiple tornadoes form and travel together in swarms.
4. Watch vs. Warning
5. Tornadoes: The Science Behind the Destruction
Read the article to answer the questions about how tornadoes form.
7. Hurricanes 101
8. Top 10 Hurricanes in History
Ten Facts About Hurricanes
2) Hurricanes form over warm ocean waters near the equator. The warm, moist air above the ocean surface rises, causing air from surrounding areas to be 'sucked' in. This 'new' air then becomes warm and moist, and rises, too, beginning a continuous cycle that forms clouds. The clouds then rotate with the spin of the Earth. If there is enough warm water to feed the storm, a hurricane forms!
3) Hurricanes rotate around a circular centre called the 'eye', where it is generally calm with no clouds. Surrounding the eye is the eye wall - the most dangerous part of the hurricane with the strongest winds, thickest clouds and heaviest rain!
4) Most hurricanes occur harmlessly out at sea. However, when they move towards land they can be incredibly dangerous and cause serious damage.
5) The strong spiraling winds of a hurricane can reach speeds of up to 320kmph - strong enough to rip up entire trees and destroy buildings!
6) In the southern hemisphere, hurricanes rotate in a clockwise direction, and in the northern hemisphere they rotate in an anti-clockwise direction. This is due to what's called the Coriolis Force, produced by the Earth's rotation.
7) When a hurricane reaches land it often produces a 'storm surge'. This is when the high winds drive the sea toward the shore, causing water levels to rise and creating large crashing waves. Storm surges can reach 6m high and extend to over 150km!
8) Hurricanes are also called cyclones and typhoons, depending on where they occur. In the Atlantic Ocean and Northwest Pacific they are hurricanes, in the Northwest Pacific they are typhoons and in the South Pacific and Indian Ocean they are cyclones.
9) The largest hurricane on record is Typhoon Tip, which occurred in 1979 in the northwest Pacific. With a diameter of around 2,220km, it was nearly half the size of the United States!
10) Hurricanes are given names by the World Meteorological Organisation (WMO) so that they can be distinguished. Each year, tropical storms are named in alphabetical order according to a list produced by the WMO. That name stays with the storm if it develops into a hurricane. The names can only be repeated after six years.
9. Hurricane Katrina: 10 Years Later
Thunderstorms & Floods
10. Thunderstorm Basics
What is a thunderstorm?
What is a severe thunderstorm?
A thunderstorm is classified as “severe” when it contains one or more of the following: hail one inch or greater, winds gusting in excess of 50 knots (57.5 mph), or a tornado.
When are thunderstorms most likely?
Thunderstorms are most likely in the spring and summer months and during the afternoon and evening hours, but they can occur year-round and at all hours.
What kinds of damage can thunderstorms cause?
Many hazardous weather events are associated with thunderstorms. Under the right conditions, rainfall from thunderstorms causes flash flooding, killing more people each year than hurricanes, tornadoes or lightning. Lightning is responsible for many fires around the world each year, and causes fatalities. Hail up to the size of softballs damages cars and windows, and kills livestock caught out in the open. Strong (up to more than 120 mph) straight-line winds associated with thunderstorms knock down trees, power lines and mobile homes. Tornadoes (with winds up to about 300 mph) can destroy all but the best-built man-made structures.
What is the difference between a Severe Thunderstorm WATCH and a Severe Thunderstorm WARNING?
A Severe Thunderstorm WATCH is issued by the NOAA Storm Prediction Center meteorologists who are watching the weather 24/7 across the entire U.S. for weather conditions that are favorable for severe thunderstorms. A watch can cover parts of a state or several states. Watch and prepare for severe weather and stay tuned to NOAA Weather Radio to know when warnings are issued.
A Severe Thunderstorm WARNING is issued by your local NOAA National Weather Service Forecast Office meteorologists who watch a designated area 24/7 for severe weather that has been reported by spotters or indicated by radar. Warnings mean there is a serious threat to life and property to those in the path of the storm.ACT now to find safe shelter! A warning can cover parts of counties or several counties in the path of danger.
11. Lightning 101
13. Effects Of Flooding
Sinkholes are pits in the ground that form in areas where water gathers without external drainage. Sinkholes mainly occur as water drains below ground. It can dissolve subterranean caverns, particularly in areas where the bedrock is made of water-soluble evaporate rocks such as salt or gypsum or of carbonate rocks such as limestone or dolomite.
What causes sinkholes?
Sinkholes can be natural or man made. Natural sinkholes occur due to erosion or underground water. They start developing long time before it actually appears. The ground beneath our feet is not as much of a solid structure as we think it is. The ground is made from dirt, along with many rocks and minerals. There is water continually seeping in between the mud, rocks and minerals, as it makes its way down to the ground water reservoirs. As this happens, the water slowly erodes the rocks and minerals. Sometimes the flow of water increases to a point when it washes away the underground structure of the land. And when the structure becomes too weak to support the surface of the earth, it collapses and opens up a hole. This is how sinkholes are formed.
What type of bedrock is more susceptible to sinkholes?
Areas that have a bedrock made of limestone, salt deposits or carbonate rock are most susceptible to erosion and the formation of such holes. These rocks tend to erode as acidic water passes through them. When rainwater passes through decaying plant debris, it tend to become more acidic. Over a period of years, overlying sediments collapse and a sinkhole develops. Sometimes the holes are small, measuring a few feet wide and ten to fifteen feet deep. Others can be hundreds of miles wide and deep. However, all of them can be dangerous for those that get caught in them. There are three major kinds of sinkholes. Their formation is determined by the same geological processes, barring a few differences.
How quickly do sinkholes form?
Most of the time, sinkholes form gradually. Occasionally, though, the collapse is sudden. Those sudden sinkholes are often the ones that open up and swallow cars, homes and streets.
What are some notable sinkholes?
In 2010 one of the most devastating sinkholes in recent times hit Guatemala City. An area approximately 65ft wide and 100ft deep collapsed, swallowing a three-story factory and killing 15 people. The sinkhole was caused by a number of factors including an influx of water from Tropical Storm Agatha and leakage from a local sewerage pipe.On February 12, 2014, a sinkhole some 40ft wide and 20ft deep opened under the floor of the Skydome area of the National Corvette Museum causing a portion of the floor to collapse. Eight rare and one-of-a-kind Corvettes, portions of the display stands and rails, large concrete floor slabs and dirt fell into the sinkhole, causing serious damage to some of the Corvettes. The Corvettes involved have an estimated value of a million dollars.
Do sinkholes happen in other parts of the world?
Yes! The deepest we know about is the Xiaozhai tiankeng in China. Tiankeng is the local term for large sinkholes and translates literally as ‘heavenly pit’. This particular example in the Chongqing district is a staggering 662m deep and 626m wide.
Other notable sinkholes include Sima Humboldt in Bolivia, a crater 314m deep and formed from extremely resistant sandstone.
The Great Blue Hole in Belize, a perfectly round hole in the middle of an atoll which is 124m deep.
Finally, Crveno Jezero in Croatia, a 530m deep sinkhole with nearly vertical walls.
15. Earthquake 101
• Geologists rate earthquakes in magnitude, which is the amount of energy released during the quake.
• The largest recorded earthquake happened in Chile on May 22, 1960. It was a magnitude 9.5.
• The deadliest known earthquake happened in China in 1556. It killed about 830,000 people.
• Alaska has the record for the largest U.S. earthquake. On March 28, 1964, a magnitude 9.2 quake occurred and killed 131 people.
• Most earthquakes happen 50 miles (80 kilometers) or less below the Earth's surface. They can happen as deep as 400 miles (644 kilometers) below the surface.
• Southern California has about 10,000 earthquakes a year. Very few are felt.
• Alaska averages 24,000 earthquakes a year, the most seismic activity in North America.
• Florida and North Dakota have the fewest earthquakes in the U.S.
• In 1985, the jolt from an 8.1 magnitude earthquake in Michoacán, Mexico caused water to slosh out of a pool in Tucson, Arizona—1240 miles (2000 kilometers) away!
• Most earthquakes and volcanos—80%—happen close to where two plates meet.
• Depending on the plate, they move between 0.3 to 5.9 inches a year (1 to 15 centimeters) a year.
• Because of moving plates, geologists predict that Los Angeles will meet Alaska ... in 70 million years! (It'll be neighbors with San Francisco in 15 million years.)
16. Biggest Earthquakes Ever Recorded
Tsunamis are huge waves of water that are usually caused by earthquakes or volcanic eruptions.
As a tsunami approaches the shore, water may recede from the coast, if it is shallow enough the water may be pulled back hundreds of meters. If you are in the area, observing this is a good indication that a tsunami is on the way.
Regions in tsunami danger zones often have warning systems in place to give people as much time to evacuate as possible.
When tsunamis hit shallow water (often near the coast) they slow down but increase in height.
An earthquake in the Indian Ocean off Indonesia in December 2004 caused a tsunami that killed over 200000 people in 14 countries.
In March 2011, the Tohoku earthquake off the eastern coast of Japan caused a tsunami that was a major factor in the death of over 15000 people.
The tsunami waves created by the Tohoku earthquake reached heights of over 40 meters (131 feet) in some areas, wiping out coastal towns and causing a number of nuclear accidents.
The Japanese word tsunami literally means ‘harbor wave’.
Tsunamis are sometimes referred to as tidal waves but this term has fallen out of favor because tsunamis are not related to tides.
- There are about 1,900 active volcanoes on the earth. This means they have erupted recently or they might erupt. Some volcanoes are extinct. Over 80 volcanoes have been found in the ocean.
- Most volcanoes happen on fault lines, or cracks in the Earth’s surface.
- Most of the earth’s volcanoes are in the Pacific Ocean, in an area called the Ring of Fire.
- The word “volcano” comes from Vulcan, the Roman god of fire.
- Lava from volcanoes can reach temperatures of 2,000 degrees Fahrenheit.
- Volcanoes spew out ash and toxic gases, as well as lava and lava boulders.
- Pompeii was an ancient city that was completely buried in ash and lava.
Drought & Wildfire
22. Droughts 101
23. All About Wildfires
A wildfire also known as a wildland fire, forest fire, vegetation fire, grass fire, peat fire, bushfire (in Australia), or hill fire is an uncontrolled fire often occurring in wildland areas, but which can also consume houses or agricultural resources. Wildfires often begin unnoticed, but they spread quickly igniting brush, trees and homes.
What causes a wildfire?
Common causes of wildfires include lightning, human carelessness, arson, volcano eruption, and pyroclastic cloud from active volcano. Heat waves, droughts, and cyclical climate changes such as El Niño can also have a dramatic effect on the risk of wildfires. Although, more than four out of every five wildfires are caused by people.
Where can wildfires occur?
Wildfires can occur anywhere, but are common in the forested areas of the United States and Canada. They are also susceptible in many places around the world, including much of the vegetated areas of Australia as well as in the Western Cape of South Africa. The climates are sufficiently moist to allow the growth of trees, but feature extended dry, hot periods. Fires are particularly prevalent in the summer and fall, and during droughts when fallen branches, leaves, and other material can dry out and become highly flammable. Wildfires are also common in grasslands and scrublands.
How do firefighters put out the wildfires?
Firefighters use a tool known as a pulaski. Its a combination of an ax and hoe used to dig a fireline. A fireline is a strip of land from which all brush and debris have been cleared to rob a wildfire of its fuel. Firefighters also use hotshots and smoke jumpers to clear a large path in a big circle around the fire so the blaze is contained in a ring of dirt. When the fire reaches this area, it runs out of fuel and starves to death. If the fire is too large, however, planes and helicopters fly overhead, dropping water and special chemicals that smother the flames. This pink, fire-retardant chemical is called sky jell-o.
24. Alberta Canada - 2016
25. Fighting Wildfires
- On average, more than 100,000 wildfires, also called wild-land fires or forest fires, clear 4 million to 5 million acres (1.6 million to 2 million hectares) of land in the U.S. every year.
- In recent years, wildfires have burned up to 9 million acres (3.6 million hectares) of land.
- A wildfire moves at speeds of up to 14 miles an hour (23 kilometers an hour), consuming everything in its path. This includes trees, flowers, bushes, animals, and houses. Some wildfires can destroy an entire town and some of its residents.
- There are three conditions that need to be present in order for a wildfire to burn, which firefighters refer to as the fire triangle: fuel, oxygen, and a heat source.
- Lightning, burning campfires or cigarettes, hot winds, and even the sun can all provide enough heat to spark a wildfire.
- Four out of every five wildfires are started by people.
- Many people now live in areas where wildfires frequently occur. Wildfires are becoming more intense because they are being extinguished before they are allowed to burn all the underbrush that acts as fuel. When fires do break out in these areas they are very intense because they have a lot of fuel.
- Dry weather and drought convert green vegetation into bone-dry, flammable fuel; strong winds spread fire quickly over land; and warm temperatures encourage combustion.
- Montana, Idaho, Wyoming, Washington, Colorado, Oregon, and California experience some of the worst forest fires in the U.S. In California wildfires are often made worse by the hot, dry Santa Ana winds, which can carry a spark for miles.
- Traditional methods of fighting a forest fire include water dousing and spraying fire retardants to extinguish existing fires. Clearing vegetation to create firebreaks starves a fire of fuel and can help slow or contain it. Firefighters also fight wildfires by deliberately starting fires in a process called controlled burning.