a. What causes flooding?
Flooding isn’t just a threat to people living near water. It happens all across the country. In all regions, in all climates, in a variety of ways. Take a look at some of the causes of flooding:
Storm surge is a large dome of water, often 50 or more miles wide, that sweeps across the coastline near where a hurricane makes landfall. Storm surge is the greatest threat to property and life along the effected coast.
Intense rainfall in a brief period leaves more water than the ground can absorb. When this happens, flash flooding can occur. Flash floods occur with little or no warning, move at very fast speeds and can reach a peak in a few minutes. They can roll rocks and boulders, tear out trees and destroy buildings and bridges.
Mudslides result from long, heavy rains on hillsides and mountainsides. The water saturates the soil and acts like a lubricant, causing soil, large rocks, boulders and homes to slip free.
This type of flooding comes when higher-than-normal spring temperatures cause snow to melt rapidly. The excess water is too much for the frozen ground to absorb.
On frozen rivers, melting snow and heavy rain break the ice into large chunks. These chunks float downstream, often piling up at bridges, dams and narrow passages. These ice jams can force water to overflow riverbanks, flooding nearby homes and businesses.
Nature isn’t the only cause of flooding.
New construction and paving alter land’s ability to drain properly. As a result, run-off can increase two to six times over what would occur on natural terrain. Areas that were initially zoned as low-risk can quickly become high-risk as urban development alters topography.
The National Flood Insurance Program (NFIP) legally defines a flood as follows:
Under the National Flood Insurance Program (NFIP) a flood is defined as a general and temporary condition of partial or complete inundation of normally dry land by:
- The overflow of inland or tidal waters.
- The unusual and rapid accumulation or runoff of surface waters from any source.
- Mudslides (i.e., mudflows) which are proximately caused by flooding, as defined above and are akin to a river of liquid and flowing mud on the surfaces of normally dry land areas, including your premises, as when earth is carried by a current of water and deposited along the path of the current.
- The collapse or subsidence of land along the shore of a lake or other body of water as a result of erosion or undermining caused by waves or currents of water exceeding the cyclical levels which result in flood as defined above.
To qualify as a general and temporary condition, the flood must affect either two or more adjacent properties or two or more acres of land and have a distinct beginning point and ending point. Also, to qualify, the flood waters can only be surface water that covers land that is normally dry.