Flooding is a coast to coast threat to the United States and its territories in all months of the year. National Flood Safety Awareness Week is intended to highlight some of the many ways floods can occur, the hazards associated with floods, and what you can do to save life and property. Details are found here.
From the FEMA:Flood Website
Floods are one of the most common hazards in the United States. Flood effects can be local, impacting a neighborhood or community, or very large, affecting entire river basins and multiple states.
However, all floods are not alike. Some floods develop slowly, sometimes over a period of days. But flash floods can develop quickly, sometimes in just a few minutes and without any visible signs of rain. Flash floods often have a dangerous wall of roaring water that carries rocks, mud, and other debris and can sweep away most things in its path. Overland flooding occurs outside a defined river or stream, such as when a levee is breached, but still can be destructive. Flooding can also occur when a dam breaks, producing effects similar to flash floods.
Be aware of flood hazards no matter where you live, but especially if you live in a low-lying area, near water or downstream from a dam. Even very small streams, gullies, creeks, culverts, dry streambeds, or low-lying ground that appear harmless in dry weather can flood. Every state is at risk from this hazard.
If a flood is likely in your area, you should:
- Listen to the radio or television for information.
- Be aware that flash flooding can occur. If there is any possibility of a flash flood, move immediately to higher ground. Do not wait for instructions to move.
- Be aware of streams, drainage channels, canyons, and other areas known to flood suddenly. Flash floods can occur in these areas with or without such typical warnings as rain clouds or heavy rain.
If you must prepare to evacuate, you should do the following:
- Secure your home. If you have time, bring in outdoor furniture. Move essential items to an upper floor.
- Turn off utilities at the main switches or valves if instructed to do so. Disconnect electrical appliances. Do not touch electrical equipment if you are wet or standing in water.
If you have to leave your home, remember these evacuation tips:
- Do not walk through moving water. Six inches of moving water can make you fall. If you have to walk in water, walk where the water is not moving. Use a stick to check the firmness of the ground in front of you.
- Do not drive into flooded areas. If floodwaters rise around your car, abandon the car and move to higher ground if you can do so safely. You and the vehicle can be quickly swept away.
Driving Flood Facts
The following are important points to remember when driving in flood conditions:
- Six inches of water will reach the bottom of most passenger cars causing loss of control and possible stalling.
- A foot of water will float many vehicles.
- Two feet of rushing water can carry away most vehicles including sport utility vehicles (SUV’s) and pick-ups.
From the New Hampshire Dept. of Safety, Homeland Security and Emergency Management web page.
Natural disasters have historically not occurred as frequently in New Hampshire as in other parts of the world, but the state has had its share. Since 2005 it has experienced a destructive series of events, including floods, a major tornado and the most serious ice storm in its history.
During Fiscal Year 2009, which began on July 1, 2008, and ended on June 30, 2009, New Hampshire received four presidential disaster declarations including all 10 counties.
The most common hazard in New Hampshire is flooding. Every year some part of the state experiences flash flooding, main stem river flooding, coastal flooding or a combination of the three.
The most recent series of floods began in October 2005 with a flood that primarily affected the southwest corner of the state and devastated the town of Alstead. The flood killed seven people. It was followed by floods in May 2006 and April 2007 and a series of floods during the late summer and early fall of 2008.
These floods all had one thing in common – continuous heavy rain caused by two or more weather systems that stalled over the state. Because of the state’s rough topography, its many small rivers and streams can quickly overflow their banks during heavy, continuous rain. There is no place for the excess water to go except onto roads and fields and into populated areas.
Historically, the state’s two largest floods occurred in 1936 and 1938. The 1936 flood was associated with snow melt and heavy precipitation. The 1938 flooding was caused by the Great New England Hurricane of 1938. Those floods prompted the construction of a series of flood control dams, built in the 1950s and ‘60s. They continue to be operated by the US Army Corps of Engineers.
The threat of flooding is most common in the spring from a combination of snow melt and rain. But floods may strike the state at any time of the year.
The Maine Cooperative Snow Survey collects, interprets, and distributes information on the depth and water content of Maine's snowpack in the late Winter and early Spring, when the danger of flooding in Maine's rivers and streams is greatest. The data are obtained from a variety of sources.