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then causes the river to rise rapidly and flood upstream. Floating debris can consist of anything from trash to aquatic plants to sticks and logs. An ice jam is composed of chunks of ice that clump together. The chance of flooding increases if the land around the river has poor drainage, such as concreted areas, or slopes toward the river because it causes more water to flow into the river. Coastal floods can occur due to the high tide and coastal storms. High tide flooding occurs when the rising sea level combines with a new or full moon. A new or full moon causes changes in the wind, ocean currents, and strong tides. When the moon’s gravitational force is met with a high tide, this can cause high tide flooding even on a sunny day. Coastal storms such as tropical storms, hurricanes, or a type of winter storm called a nor’easter , can also cause coastal flooding. These storms change ocean wave patterns and can cause significantly higher waves that crash into the coast and flood dry land. Coastal flooding occurs in Charleston, South Carolina, and Savannah, Georgia, several times a year due to the coastal development and lower elevation. Coastal development is the construction of homes, hotels, restaurants, and roads along the coast. These structures prevent the coast’s ability to shield dry land from these powerful storms. Earthquakes can also cause coastal flooding by creating a massive wave known as a tsunami. These tsunami waves are strong enough to reach inland up to 100 feet above sea level. Additionally, coastal floods are also caused by storm surges, an unusual rise in seawater level during a storm. Storm surges can be more threatening when they occur at the same time as high tide and can cause some tides to reach up to 20 feet along the

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What Makes a Flood