Extreme Weather Events
Know about extreme weather events: hurricanes (spinning storms over warm ocean), tornadoes (violent rotating columns of air), floods, droughts, and blizzards, how they form, where they typically occur, and their effects on people and the environment
What a learner can do afterwards
- Describe how at least two types of extreme weather form
- Explain where hurricanes and tornadoes typically occur and why
- Describe the effects of extreme weather on communities and landscapes
1 · Read
You know puddle water rises into the air and clouds are tiny drops or bits of ice together. Moving air is called wind. Extreme weather uses those same ideas on a much bigger scale. Hurricanes, tornadoes, floods, droughts, and blizzards are called extreme weather because they are far stronger than an ordinary day, and they can change a place fast.
A hurricane is a giant spinning storm that forms over warm tropical ocean water. The warm water evaporates quickly, and that moist, heated air rises fast and starts to spin as Earth turns beneath it. The storm grows a calm center called the eye, ringed by strong wind and rain. Hurricanes only form where the ocean is warm enough, so they stay over tropical water until they drift toward a coastline.
A tornado is a violent, spinning column of air that drops down from a powerful thunderstorm. It forms over land when warm, humid air crashes into cool, dry air and starts to twist upward. In the United States, this collision happens often in a region nicknamed Tornado Alley, where warm air from the Gulf of Mexico meets cool air from the Rocky Mountains. Unlike hurricanes that need warm ocean water, tornadoes form over land.
In 2005, Hurricane Katrina formed over warm Atlantic water, grew stronger for days, and then struck the Gulf Coast of the United States. Storm surge and heavy rain flooded whole neighborhoods, and some communities took years to rebuild. Other extreme weather leaves its own mark: a flood can coat streets in mud, a drought can dry up crops and rivers, and a blizzard can bury roads in snow and cut off power for days.
Hurricanes spin up over warm ocean water, tornadoes spin down from thunderstorms over land, and every kind of extreme weather reshapes the place it hits.
The rewritten readings were written for this dataset.
More to read
Teachable Moment: NASA's Eyes on Extreme Weather
Extreme weather means weather that is much stronger or stranger than usual. Hurricanes are giant spinning storms that grow over warm ocean water. Floods happen when too much rain falls and rivers spill over their banks. Droughts are long stretches with little or no rain, so the land dries out and crops can die. Wildfires spread fast when the land is dry. Scientists at NASA use satellites in space to watch these events from above. The satellites help them see where storms are heading and warn people early, so families have time to get to safety.
How tornadoes spin
A tornado is rotating air that connects a storm cloud to the ground. The strongest tornadoes may have winds near 500 kilometers per hour, enough to destroy houses and throw cars. Some have a broad top and a thin lower end, though their shapes vary. Narrowing airflow can speed up rotation, but the fastest winds are not always at the bottom. Tornado Alley is a central US region known for tornadoes. Warm, moist air meeting cooler, dry air can help storms develop, but tornadoes also occur elsewhere.
Tracking a hurricane
Hurricanes develop above warm seas. Heat from the water helps moist air rise, and surrounding air moves inward to replace it. Earth's rotation helps curve the winds into a rotating storm. Weather scientists, called meteorologists, study these winds to forecast the storm's path. Warnings give coastal communities time to prepare or leave before it reaches them. Astronauts aboard the International Space Station took photographs of Cyclone Catarina over the South Atlantic Ocean in 2004.
Shelter in a car during a blizzard
Blizzard winds blow falling or loose snow so thickly that seeing is difficult. If snow traps your car and it is safe inside, stay there for shelter and to help rescuers find you. For warmth, an adult may run the engine briefly, but must keep the exhaust pipe clear and a window slightly open to reduce the risk of poisonous fumes. Pack blankets, drinking water and food for winter trips. Check the weather forecast before leaving to avoid driving into a storm.
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2 · Watch
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Where it sits
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Optional connections
Where this leads
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8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.