Natural disasters are powerful events caused by Earth processes, weather, climate, or environmental conditions. This cheat sheet helps students compare common disaster types, recognize warning signs, and understand why some places are at higher risk. It is useful for reviewing Earth science vocabulary, cause and effect, and safety planning.
Key Facts
- An earthquake is sudden shaking of the ground caused by energy released when rocks break or slip along a fault.
- A volcano is an opening in Earth's crust where magma, ash, and gases can reach the surface during an eruption.
- Floods happen when water covers land that is usually dry, often after heavy rain, storm surge, snowmelt, or dam failure.
- A hurricane is a large rotating tropical storm with winds of at least 74 miles per hour that forms over warm ocean water.
- A tornado is a narrow, rotating column of air that extends from a thunderstorm to the ground and can cause extreme wind damage.
- Drought is a long period with much less precipitation than normal, which can reduce water supplies, damage crops, and increase wildfire risk.
- Wildfires spread fastest when dry fuel, oxygen, heat, and wind are present, which is often called the fire triangle plus wind.
- Risk depends on both hazard and exposure, so Disaster risk = natural hazard + people or property in harm's way.
Vocabulary
- Natural disaster
- A natural event that causes major damage, danger, or disruption to people, property, or the environment.
- Hazard
- A possible source of danger, such as a fault, storm, floodplain, volcano, or dry forest.
- Fault
- A crack in Earth's crust where blocks of rock can move and cause earthquakes.
- Storm surge
- A rise in ocean water pushed onto land by strong storm winds, especially during hurricanes.
- Evacuation
- The act of leaving a dangerous area and moving to a safer place before or during an emergency.
- Preparedness
- Planning and practicing what to do before a disaster so people can respond quickly and safely.
Common Mistakes to Avoid
- Confusing weather and climate is wrong because a single storm is weather, while climate describes long-term patterns over many years.
- Thinking all earthquakes happen at the surface is wrong because many begin underground at a focus, then shaking spreads outward as seismic waves.
- Assuming floods only happen near rivers is wrong because flash floods can occur in streets, deserts, valleys, and low areas after intense rain.
- Trying to outrun or watch a tornado is unsafe because tornadoes can change speed and direction quickly, so people should move to a sturdy shelter.
- Believing natural disasters can always be prevented is wrong because many hazards cannot be stopped, but preparation can reduce injuries and damage.
Practice Questions
- 1 A hurricane has winds of 80 miles per hour. Does it meet the minimum wind speed for a hurricane, and by how many miles per hour is it above the minimum?
- 2 A town receives 6 inches of rain in 3 hours. What is the average rainfall rate in inches per hour?
- 3 An earthquake starts 20 kilometers below Earth's surface. Is the starting point called the focus or the epicenter?
- 4 A coastal city, a desert town, and a mountain forest each face different disaster risks. Explain why location affects the types of natural disasters people should prepare for.