Natural Disasters. in Florida. Severe Thunderstorms

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1 Natural Disasters in Florida SC.6.E.7.7 Investigate how natural disasters have affected human life in Florida. Severe Thunderstorms While the typical afternoon thunderstorm in Florida may not appear to be a natural disaster, the heavy rainfall and frequent lightning strikes that accompany these storms can impact people and their daily activities. Florida has almost three times more lightning strikes annually than any other state. Additionally, approximately half of the deaths due to severe weather in Florida are attributed to lightning strikes. As a result, outdoor activities often are postponed during afternoon thunderstorms and people are encouraged to seek shelter. Hurricanes Stronger and more severe than thunderstorms, hurricanes are a common occurrence in Florida. The state s coastlines suffer the greatest amount of damage from hurricanes because most of this land is at or near sea level. There are few natural barriers to hold back rising water or to block the strong winds. Satellite image of Hurricane Hugo as it approaches the east coast of Florida. 1

2 Damage from Hurricane Andrew in Miami-Dade County, Florida Florida s Hurricane History From 1851 to 2010, more than 1,200 tropical storms and hurricanes made landfall in Florida. Thirty-seven of these storms ranked as category 3 hurricanes and above on the Saffir Simpson Scale. The 1935 Florida Keys Labor Day hurricane ranked as a category 5 storm and remains the strongest hurricane ever recorded in the United States. Hurricane Donna made landfall in 1960 and ranked as a category 4 storm. Donna spanned the entire length of the eastern seaboard with sustained wind speeds of more than 325 km/h. In 1992, Hurricane Andrew became one of the costliest and most destructive hurricanes to date as it traveled across Florida and into the Gulf of Mexico. Combined, the estimated economic damage from hurricanes in the state of Florida exceeds $115 billion. High Winds and Rain Hurricanes with high sustained wind speeds usually cause the greatest amount of damage. The damage is caused not only by the strong winds but also by the materials that the wind carries, which includes dust and debris, pieces of damaged buildings, and other materials swept up by the storm. Along with strong winds, hurricanes are also associated with heavy rains and storm surges, which can lead to flooding. MAJOR Florida Hurricanes Hurricane Year Category Florida Landfall Estimated Damage Galveston Florida Keys $30 million in US Okeechobee Palm Beach $25 million Labor Day , 2 Florida Keys, Cedar Key $6 million Donna Florida Keys $387 million in US Agnes Florida panhandle $2.1 billion in US Andrew southern Florida $25 billion Charley Captiva Island $15 billion in US Katrina Miami-Dade County $75 billion in US 2

3 Storm Surges and Flooding A storm surge is water that has blown outward from the center of a hurricane, eventually sweeping up onto the coastline as a large wave. The storm surge can extend beyond a radius km outside of the hurricane, is typically 2 3 m high, and causes flooding onshore. With over 60 percent of Florida s population living within 8 km of the coast, floods from a storm surge can threaten human life and property in Florida. Florida has a flat landscape with most coastal areas only 2 3 m above sea level, enabling the storm surge to travel inland more than 2 km. Water that flows into these lowlying areas can remain there for weeks. Beach homes, restaurants, hotels, and other structures that line the Florida coastline are damaged; boats docked in the ocean are thrust inland; and cars can be tossed out to sea. The currents created by the tide, the weight of the water, and the action of the waves can destroy beaches and coastal highways. Even a large building designed to withstand a hurricane s wind can be destroyed when water weakens its foundation. Another effect of hurricanes and storm surge is significant beach erosion. While Florida s beaches are the first line of defense in protecting low-lying areas, a storm surge can easily remove and relocate sand dunes. Because 2,000 km of Florida s coastlines lie in the main path of many hurricanes, few years pass without a hurricane or tropical storm affecting Floridians and their property. This makes storm-related beach erosion a serious issue for the state. Federal and local governments spend billions of dollars every year restoring beaches along Florida s coastline. Erosion from storm damage at Vero Beach 3

4 Tornadoes When a hurricane hits land, it can spawn tornadoes. Tornadoes also can occur during thunderstorms. Because Florida experiences tornadoes with both thunderstorms and hurricanes, the state has the highest overall tornado average per square mile in the nation. Tornadoes can cause tremendous amounts of damage when they touch down on land. Seven tornadoes with wind speeds between km/h touched down during the Central Florida Tornado Outbreak in Melbourne County in The outbreak killed 42 people, and more than 260 others were injured. More than 3,000 structures were damaged and 700 destroyed, leading to property damage in excess of $100 million. Tornadoes that form over warm water are called waterspouts. Waterspouts are common along the Gulf Coast, particularly around Florida. On occasion, they travel inland and cause damage and injuries. However, this is rare because waterspouts usually dissipate over land. Droughts and Wildfires Drought is also common in Florida. Water conservation practices are encouraged during times of drought. For example, during droughtlike conditions, communities issue water restrictions that designate certain days for washing cars and watering lawns. When a rainy season is followed by severe drought conditions, wildfires can result. The rainy season can yield a lush covering of understory brush, which is vulnerable to burning when drought conditions follow. Lightning strikes, which are abundant in Florida, can start wildfires. In May 2008, nearly 40,000 acres of park land burned in Everglades National Park. Every year, thousands of acres of wilderness and many homes are destroyed by fire. In addition to these immediate damages, wildfires can continue to impact an area s ecosystems once the fire is out. These aftereffects include risks of floods, extensive soil erosion, landslides, and reduced water quality. A wildfire threatens these Florida homes. 4

5 Sinkholes Another natural disaster Florida experiences more than any other state is sinkhole formation. A sinkhole forms when areas underlain by limestone and dolomite dissolve due to the presence of acid rainwater. This can occur in normal precipitation conditions, but especially after periods of drought or heavy rainfall. The overlying rock and soil then collapse and form a depression. Sinkholes are particularly problematic in densely populated areas where they can harm people and damage property. However, they also impact Florida s population when they occur in less-populated areas. For example, in 1999, Lake Jackson began to disappear when an 8-ft sinkhole opened in the bottom of the lake. After a few days, the large lake, well-known for its fishing, was drained of its water, fish, and alligators. This lake drains approximately every 25 years into various sinkholes. Make a poster Use the information in the previous pages to design a poster that summarizes how natural disasters affect human life in Florida. Share your poster with the class. SC.6.E.7.7 5