Hurricanes By Sarah and Jordan

How Hurricanes Form  1. Thunderstorm grows a little bit, combines with other thunderstorms, and they all spin around an area of low pressure (tropical depression).  2. The storm grows some more, its winds become stronger, and it is called a tropical storm.  3. The storm grows even more, its winds become even faster, and now it is called a hurricane.  Hurricanes get their energy from the warm ocean water.  When over warm water it will grow.  A hurricane dies when it moves away from the warm water.  When moving into areas with cooler ocean water, it weakens.  Will also weaken if it travels over land.

How they are measured  The Saffir-Simpson scale is The standard scale for rating the severity of hurricanes. This scale is based on the observations of many North Atlantic hurricanes.  The Saffir-Simpson Hurricane Scale rates hurricanes from category 1 through category 5 in order of increasing intensity. Each intensity category specifies the range of conditions based on four criteria: barometric (central) pressure, wind speed, storm surge, and damage potential.

Saffir-Simpson Scale  Category 1- some damage to trees and non-anchored homes, mild flooding is expected to occur.  Category 2- considerable damage to trees…causing them to be blown down, more extensive damage to poorly anchored houses  Category 3- trees blown down, minor structural damage to buildings, more severe flooding will take place.  Category 4- severe damage to roofing and houses, damage to coast line structures due to severe flooding.  Category 5- small buildings swept away, major structural damage occurs-- evacuation of all living near the coast due to disastrous flooding.

Where do they occur?  Occur in the tropical convergence zones… AKA the warm regions of the earth  Happen all around the world!

Warning System for Hurricanes  The main governing body for warning the United States for a potential hurricane is the National Hurricane Center (aka NHC) that is based in Miami, Florida  The National Hurricane Center is apart of the National Oceanic and Atmospheric Administration  The NHC sends out these warnings to news media of the area that could potentially be affected  The website is

How to Stay Alive During a Hurricane  Do NOT use the elevators.  If in a mobile home, secure tie downs and leave at once.  If you are secured in your home: –Stay AWAY from glass and windows. –Have all emergency supplies ready. –Turn all appliances off if power is lost.  If evacuation is needed: –Unplug all appliances and turn off electricity and the main water. –Bring emergency supplies and blankets and sleeping bags as shelter. –Leave as soon as you secure your house  DO NOT go outside until authorities inform you that the weather is clearing up

Most Severe Hurricane  In terms of Intensity, here are the top five most powerful hurricanes: 1.Hurricane Wilma, recorded in Hurricane Gilbert, recorded in “Labor Day” Hurricane, recorded in Hurricane Rita, recorded in Hurrricane Allen, recorded in 1980  In terms of Deaths, the top five hurricanes are: 1.Super Typhoon Nina, recorded on 1975 with 210,000 deaths 2.Calcutta Cyclone, recorded on 1737 with 300,000 deaths 3.Haiphong Typhoon, recorded on 1881 tying Calcutta Cylcone death toll 4.Indian Cyclone, recorded on 1839 with 325,000 deaths 5.Bhola Cyclone, recorded on 1970 with 500,000 deaths