Catastrophic Events

1. Catastrophic Events

2. Catastrophic Events • What is a Catastrophic Event? • Any event naturally occurring or caused by human action that: • Causes severe damage to the land • Endangers life OR causes loss of life • Speeds up the effects of erosion and deposition • Also known as natural disasters

3. Tornadoes • Winter and Early Spring • Develop from Thunderstorms in warm moist air before east-ward moving cold fronts. • Extreme low pressure creates rotating winds which causes materials to be sucked up into a forming funnel like a vacuum • High speed rotating winds often greater than 250 mph • Ranked from F-0 Tornado (light damage such as broken tree limbs) to F-5 Tornado (total demolition of and area including concrete sucked up from the ground) • Can take lives (human and animals) and destroy property • Uproot trees and scour soil off ground • Loss of vegetation could hinder plant and animal • interaction • Causes wind erosion to soil

4. Droughts • Can be caused by interruption of the water cycle through lack of rain, water vapor condensing or even mountains preventing moisture from lowering. • Can also be caused by diverting too much water for irrigation. • One year is usually not long enough for severe drought • Dry spells lasting two or more years cause serious problems with water not being restored. • Surface and subsurface water will become below normal (will affect humans, animals and vegetation) - crop failures - livestock death • When plants die, soil will erode faster • Will increase forest fires, sand storms and water shortages – the cycle continues

5. Wildfires • Lighting • Drought conditions with a lot of wind and low humidity (dry air) • Careless handling of fire (campers, cigarettes, arsonists) • Wildfires produce their own winds that are 10 times stronger than most winds • Fires can be beneficial for maintaining balances in ecosystems if properly managed and controlled • Can destroy millions of acres of land • When vegetation is burned, area is prone to erosion • Animals become endangered from habitat destruction • If it sweeps through inhabited areas, huge economic losses can impact humans and even whole communities • Affects air quality and also water quality.

6. Flood • Overflowing of water onto a normally dry piece of land. • Intense and long periods o f precipitation (thunderstorms or hurricanes) • Melting snow and ice • Floods are controlled by a few factors: - amount of water building up - how porous the soil is (able to absorb water) - how much water is already in the soil • Humans have altered the earth by paving it (foundations, roads, parking lots) and paved things aren’t porous which makes what falls, runoff. • Floods cause loss of life, disease (by contaminated drinking water), property loss or damage, and destruction of soil (erosion) for crops and livestock.

7. Hurricanes/Typhoons/Cyclones • Warm, moist air (above the oceans) rises and cools creating clouds • Air from the ocean surface rushes upward • As wind ruses upward it begins to spiral • This causes a tropical storm with high winds; but when the winds reach 74+ mph, it is labeled a hurricane. • Hurricane winds blow in a spiral around a calm center called an “eye” • Storms can be up to 400 miles in diameter with eyes 30 miles wide • Hurricanes may last a week or more • Hurricanes in different regions are called different names: - Atlantic Ocean = Hurricane; Pacific Ocean = Typhoon; Indian Ocean = Cyclone • Hurricanes cause other natural disasters like flooding and tornadoes • Hurricanes uproot trees and also destroy animal life by destroying habitats and defoliating vegetation. • Because of the high winds, hurricanes deposit sediment upstream in rivers that could upset the river ecosystem, but they can also erode the soil due to water movement or flooding. • Produce many deaths because of “drowning” in flood waters or storm surge.

8. EARTHQUAKES • Vibration of the Earth’s surface that occurs after a release of energy in the crust. • This release can be from a volcanic eruption, or movements of segments called faults. • Can also be caused by plate tectonic collisions. • The Earth’s crust may actually bend as pressure builds and then finally exceeds the strength of the rock. At that point the crust will break and snap into a new position. • This process will release any pressures resulting in equilibrium for the crust. • Seismic “waves” are created in from the center and will travel outward at varying speeds. Can be measured on a “Richter” Scale. • Can open large cracks in the ground (have even been known to make whole bodies of water disappear). • Can raise, lower or move large pieces of land. • Earthquakes hurt the environment by causing soil liquefaction, debris slides, fires or even tsunamis if earthquakes occur on the ocean floor.

9. Tsunamis • Ocean waves produced by earthquakes, volcanic eruptions. • Can also be caused by a meteorite impact, or underwater landslides. • Waves travel between 450-650 mph. • Once a tsunami forms, the waves travel outwards in all directions. But as the waves approach the coast, they get slower and higher. • There is not just one wave; it is a series of waves (can be 90 minutes in between waves), and the first one is usually not the most severe. • Often waters will pull back from the shore before the waves arrive. • Tsunamis come ashore as rapid, turbulent, and debris filled. • They can travel up stream in rivers. • Impacts are both environmental and human: drowning, flooding, and contaminated drinking water, loss of habitat, broken gas lines (which can also cause fires) and infrastructure destruction in general.

10. Volcano • A Volcano is a vent in the Earth that allows molten rock (magma) to escape. • When pressure builds from gases in the magma, an eruption occurs. • After an eruption, the Earth moves into a state of equilibrium until gases build again. • Eruptions can be slow or violent. • Can create new, rich and fertile land (so plants return quickly). • Can also produce other disasters like earthquakes, flash flooding, and tsunamis. • Produce hazards like searing hot and poisonous gas, lava, and debris flows. • Can also destroy plants and produce greenhouse gases. • Mammals and insect life and their habitats (even coral reefs) can be destroyed. • Produces ash which makes it hard to breath and can even collapse roofs, disturb machinery, and cause jet engines to fail. This ash can even affect plants/animals/ecosystems across the planet.