Winter is soon going to be behind us. Therefore, we need to look at our spring time flooding concerns. The following are thoughts to consider with regard to what to expect as a result of a strong winter season such as the one we are hoping to exit in the near future.
Snowmelt Runoff
During the winter months, most of the precipitation is simply stored as snow or ice on the ground. During the spring, huge quantities of water are released, which explains our heavy spring runoff and flooding. Floods resulting from snowmelt runoff combined with heavy rains are the most common type of flooding in our state. These floods generally occur in the spring but will also occur during sudden winter thaws. Heavy runoff can result from the rapid melting of the snow under the combined effect of sunlight, winds, warmer temperatures and even the level of humidity in the air. When the ground is frozen, the water produced by the melting snow is unable to penetrate and runs off over the ground surface into streams and lakes. If there is an above-average snow depth, a sudden thaw, heavy rainfall, or a combination of these
factors, then the potential for high volumes of runoff and subsequent flooding increases. The later the thaw, the more likely that warm temperatures will lead to a sudden release of runoff. Since the climatic factors influencing the rate of snowmelt are often widespread, snowmelt runoff flooding conditions can exist over vast areas.
Flash Floods
Flash floods can be extremely dangerous. Unanticipated, they usually happen on small watersheds as a result of a torrential downpour, often caused by heavy thunderstorm activity. A flash flood is characterized by the occurrence of the peak of the flood within six hours of the onset of rainfall. The flood conditions develop rapidly because the rainfall is so heavy and the ground is incapable of absorbing the water quickly enough, resulting in a very high runoff rate. Flooding of this type is generally localized, very intense and damage is usually restricted to a limited area. In some cases small streams can overtop their banks, even in a drought year.
Flooding can also result from the failure of dams or other hydraulic structures, when a veritable wall of water can go hurtling down the river channel. As might be expected, the suddenness and magnitude of such an event, which is almost always the result of human failure in design, construction or operation, has disastrous results.
What can Residents do today?
Residents are reminded that protecting themselves from flooding requires simple action, including: storing important documents in a safe, dry area and purchasing flood insurance to protect their financial investment. FEMA also offers the following tips to prepare for flooding:
Before a Flood
Have a safety kit with drinking water, a first-aid kit, canned food, a radio, flashlight and blankets.
Know safe routes from home, work and school that are on higher ground.
Protect your property. Some homeowners insurance may not cover flooding.
Make sure that your flood insurance policy is up to date.
During a Flood
If flooding occurs, go to higher ground. Get out of areas subject to flooding. This includes dips, low spots, canyons, washes, etc.
Avoid areas already flooded, especially if the water is flowing fast. Do not attempt to cross flowing streams.
Roadbeds may be washed out under flood waters. NEVER drive through flooded roadways. Seek higher ground.
After a Flood
Do not turn the electricity back on in your home if you detect gas or if the electrical system has been flooded.
Wear gloves and boots to clean and disinfect everything that was touched by floodwaters or mudflows and throw out any such food stuffs.
Follow directions from local officials regarding the safety of drinking water.
Flood insurance is available through approximately 90 insurance companies in more than 20,500 participating communities nationwide. Individuals can learn more about their flood risk and how to protect their property by visiting www.FloodSmart.gov or by dialing 1-800-427-2419.
Philipp Baumann
Emergency Management Director, North Stonington
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