Hurricane mayhem This is what a hurricane strike zone can look like Hurricane Sandy caused this destruction in New Jersey in 2012 A hurricane’s high winds are incredibly destructive They can also spawn tornadoes which wreak further havoc Spiraling speeding winds can uproot trees knock over buildings fling deadly debris around sink or ground boats and toss vehicles about as if they were nothing but toys However these deadly winds are not the only dangers Hurricane Horrors When the heavy rains that hurricanes drop cause floods water suddenly covers areas of land that are usually dry drowning people and washing away anything that is not fixed to the ground Heavy rains can also soak mud-covered hillsides making the dirt so heavy and loose that it slides downhill suddenly Landslides like this can bury anything in their way and can occur many miles inland When hurricanes cause high waves that hit the coast homes and businesses along the shore can be devastated Anyone inside the buildings can be killed In fact flooding kills more people than the strong winds do 6
Hurricane Scale There are five types or categories of hurricane based on their greatest wind speed The Saffir-Simpson Hurricane Wind Scale ranks hurricanes on a scale from 1 to 5 1 being the weakest and 5 being the strongest Category 1 74 to 95 mile-per-hour 129 153 km h winds that can damage roof tiles gutters power lines and poles snap large tree branches and topple some shallow-rooted trees Category 2 96 to 110 mile-per-hour 154 177 km h winds that can damage mobile homes and roofs and blow down trees These winds can cause power outages Category 3 111 to 129 mile-per-hour 178 208 km h winds that cause more serious damage to buildings destroy mobile homes and blow down larger trees Category 4 130 to 156 mile-per-hour 209 251 km h winds can cause so much damage that they can make an area impossible to live in for months Category 5 More than 157 mile per-hour 252 km h winds cause widespread catastrophic damage and damage or destroy almost all buildings and life in their path DEADLY DATA Category 5 hurricane winds blow as fast as some high-speed trains travel Wind-whipped waves during a hurricane can dump heavy boats from ports far inland 7
CHAPTER 2 WIND POWER If you were on a boat at sea you would probably take cover if you saw dark menacing storm clouds in the distance Storm clouds often bring heavy rain but if the conditions are right they can also grow into ferocious hurricanes Storms Form Air above the ocean is warmed by the sun’s rays The heat also evaporates water into water vapor The moist warm air rises upward because it is lighter than colder air above it Cold air blows into the gaps left by warm air and is warmed itself This rise of air is called convection High in the sky the warm air cools and the water vapor condenses into rain in a cloud Condensation releases heat energy that helps warm the surrounding air Rain clouds can change into thunderstorms when temperatures rise Convection speeds up and thunderstorm clouds grow tall At the top of the cloud it is so cold that water droplets freeze into ice particles Powerful winds in the cloud bash ice particles together This process produces lightning Thunder is the sound of air expanding when heated up fast by the incredibly high temperatures of lightning The power of a hurricane builds from the sun’s warmth heating tropical seas 8
Hurricane-force winds whip calm oceans into tall punishing waves Getting Faster Convection and energy release step up another gear when the ocean water is warm This heat energy fuels a hurricane Winds start to spiral faster and faster A tropical storm has winds of 15 5 miles per hour 25 km h or more When the speeds reach 75 miles per hour 120 km h the storm has become a hurricane DEADLY DATA Water at the surface of an ocean needs to be 79 Fahrenheit 26 C or higher to supply enough energy for hurricane formation A few degrees can make a big difference to hurricane strength A category 5 hurricane Patricia which blasted Mexico in 2015 was the most powerful ever recorded It formed over water at 86 Fahrenheit 30 C 9
