H


uge hurricanes spin. Floodwaters rise.


Droughts scorch the ground. Heat waves and deep freezes grip the planet. Extreme weather is battering nearly every


corner of Earth. It’s breaking records and causing natural disasters. It’s also raising questions. What’s up with the weather? Is something pushing it to extremes? Or are these disasters just part of normal weather patterns? Meteorologists are trying to answer these


questions. T ey study weather disasters for clues. T ey look for whether or not weather patterns are changing. It will take time to figure that out. Weather


patterns change over a long period of time. So one disaster doesn’t prove anything, but many disasters might. Solving the mystery is important. It could help warn people about bad weather in the future.


Weather Patterns Meteorologists know that the weather oſt en follows a pattern. It’s the result of how the sun, ocean, and wind interact. When the sun shines on Earth, its energy


warms the ocean. Soon, the water gets warm enough that it evaporates. It changes from a liquid into a vapor that rises into the air. As this water vapor rises, winds push it. T e


biggest winds blow in patterns. T ey circle the planet. Ones near the Equator and the poles blow east to west. Others blow west to east. All these winds can carry the vapor long distances. Eventually, air cools the vapor and turns


it back into a liquid. T en it falls back to the ground as precipitation, such as rain. T is process is called the water cycle. T e weather usually follows these patterns.


So meteorologists oſt en can predict the weather for a specific place and time. Now, though, it’s getting harder. Surprising things are happening. Take what happened in a city in the southern


United States (U.S.). May is usually its wettest month. It gets about 14 cm (5.5 inches) of rain. So no one was surprised when it started raining.


18 NATIONAL GEOGRAPHIC EXPLORER


Rising Water T e rain made puddles. It filled creeks. Still, it fell. Puddles turned into lakes. Creeks overflowed. Water gushed over a highway, trapping cars and trucks in the rising water. A building even floated down a highway! In some places, families climbed on the roofs of their houses to escape floodwaters. By the time the storm ended a few days


later, it had dumped 43 cm (17 inches) of rain on the city. T is was no ordinary storm. Meteorologists had predicted rain. No one


expected so much, though. It caused the kind of flood that happens once in 1,000 years in this part of the world. T is disaster wasn’t unique. Soon aſt er,


heavy rains fell for a week in Pakistan. Rivers overflowed. By the time the rains stopped, water covered a fiſt h of the country. A few months later, rain drenched part


of Australia. Roads there disappeared under floodwaters. In many towns, only houses and treetops stuck up out of the water. T e floods trapped people. In fact, it was


dangerous to go out. Normally, crocodiles stay near rivers. Now, crocodiles swam down the flooded city streets!


Water Ways Follow the water cycle.


Warm water evaporates, forming a vapor that rises into the air.


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