According to NOAA, most floods start with slow-moving thunderstorms, thunderstorms that travel the same path several days in a row, or hurricanes. Floating debris and ice sometimes form a temporary dam which causes the water to back up until the debris breaks free, releasing a wall of water and causing flooding downstream.Continue Reading
Some rivers flood seasonally with rains. Warm rains in mountain areas melt snow to increase the volume of water in the river. Hurricanes or tropical storms bring large amounts of rain inland and cause the flooding of streams and rivers.
Urbanization increases the flood potential. The covering of formerly grassy pastures with asphalt increases the runoff from two to six times. Urban flooding turns streets into rivers. A basement in an urban setting becomes a potential death trap due to flooding.
NOAA warns residents to know the flood dangers for where they live. Most floods occur with some warning, and it is important to evacuate on the recommendation of officials. Floodwaters of only 6 inches have the ability to knock a human off his feet. If the water is over 2 feet in depth, it will float an automobile. Each additional foot of water adds another 500 pounds of lateral force to move the vehicle downstream.Learn more about Storms
Hurricanes form over the Atlantic or Pacific Ocean near the Equator when the surrounding water is at least 80 degrees Fahrenheit, according to SciJinks. The term "hurricane" typically refers to tropical storms in the Western Hemisphere, but similar weather conditions occur worldwide and are known as tropical cyclones or typhoons.Full Answer >
According to the National Center for Atmospheric Research, external winds can propel hurricanes across the ocean at sustained speeds of between 10 and 20 mph. Internally, hurricanes' wind speed is considerably higher.Full Answer >
Hurricanes form over warm ocean water when the air is cooler above. Winds must be at the surface of the ocean and spiral air inward for the hurricane to form.Full Answer >
Hurricanes are blown around the planet by the prevailing global winds. When a hurricane forms in the Atlantic Ocean, it comes together in a band of winds called the trade winds, which blow east to west in the low latitudes. Once a hurricane approaches land, local weather conditions become a much larger factor in its movement. In particular, high pressure zones can stall or divert a hurricane from its path.Full Answer >