What is a Flood?

Anywhere it rains, it can flood. A flood is a general and temporary condition where two or more acres of normally dry land or two or more properties are inundated by water or mudflow. Many conditions can result in a flood: Tropical storms and hurricanes, La Nina, outdated or clogged drainage systems and rapid accumulation of rainfall.

Just because you haven’t experienced a flood in the past, doesn’t mean you won’t in the future. Flood risk isn’t just based on history, it’s also based on a number of factors: rainfall, river-flow and tidal-surge data, topography, flood-control measures, and changes due to building and development.

Flood Hazard maps have been created to show different degrees of risk for your community, which help determine the cost of flood insurance. The lower the degree of risk, the lower the flood insurance premium. A & M Insurance Services, Inc. can provide you a quote.

Common Causes of Flooding

• Hurricanes and tropical storms can pack a powerful punch, with soaking rain, flying debris, high winds and tidal surge. In addition to causing extensive damage in coastal areas, they often bring flooding hundreds of miles inland with torrential rains and high winds, posing a threat to millions of people who don’t even live on a shoreline. Eight of the ten most expensive Federally-declared disasters have been caused by hurricanes. Everyone needs to protect themselves from the dangers of Hurricane Season. Most policies take 30 days to go into effect, so the time to prepare is now.

• Heavy Rains.   Several areas of the country are at heightened risk for flooding due to heavy rains. This excessive amount of rainfall can happen throughout the year, putting your property at risk.   Storms over the Pacific Ocean bring heavy rains to the western United States between the months of November and April. Cresting rivers, backed-up storm drains or saturated ground can cause significant floods across the region during this time.

• La Niña is characterized by unusually cold ocean temperatures in the Equatorial Pacific (unlike its brother El Niño, which is characterized by unusually warm ocean temperatures in the Equatorial Pacifc). Each La Niña event is unique and can vary in strength, impact and duration. The current La Niña is quite strong and forecasters cannot rule out the possibility that it might last throughout the year.

• Spring Thaw.  During the spring, frozen land prevents melting snow or rainfall from seeping into the ground. Each cubic foot of compacted snow contains gallons of water and once the snow melts, it can result in the overflow of streams, rivers and lakes. Add spring storms to that and the result is often serious, spring flooding.   A midwinter or early spring thaw can produce large amounts of runoff in a short period of time. Because the ground is hard and frozen, water cannot penetrate and be reabsorbed. The water then runs off the surface and flows into lakes, streams and rivers, causing excess water to spill over their banks.

• Mudflows are rivers of liquid and flowing mud on the surface of normally dry land, often caused by a combination of brush loss and subsequent heavy rains. Mudflows can develop when water saturates the ground, such as from rapid snowmelt or heavy or long periods of rainfall, causing a thick liquid downhill flow of earth. Mudflows are different from other earth movements, such as landslides, slope failures, and even moving saturated soil masses in which masses of earth, rock, or debris move down a slope where there is not a flowing characteristic.   Damage from mudflows is covered by flood insurance; damage from landslides and other earth movements is not.

• Flood After Fire.  Many areas in the western states are at an increased flood risk due to wildfires in recent years. After a wildfire, the charred ground where vegetation has burned away cannot easily absorb rainwater, increasing the risk of flooding and mudflows over a number of years. Wildfire-affected areas include states such as Arizona, California, Idaho, Nevada, Oregon and Washington. Properties directly affected by fires and those located below or downstream of burn areas are most at risk.

• New Development.  Construction and development can change the natural drainage and create brand new flood risks. That’s because new buildings, parking lots, and roads mean less land to absorb excess precipitation from heavy rains, hurricanes, and tropical storms.

• Dams. Dams are an important resource in the United States, providing many functions, including recreation, flood control, irrigation, water supply and hydroelectric power.  More than a third of our nation’s dams are already 50 years old. About 14,000 of those dams pose a “high” or “significant” hazard to life and property if failure occurs. There are also about 2,000 “unsafe” dams in the United States and in almost every state. So, while dams are built not to fail, they do.

Content provided by FloodSmart.gov