Flood Safety
Flooding is a coast to coast threat to the United States and its territories nearly every day of the year.
What is the difference between a Flood Watch and a Flood Warning issued by the National Weather Service?
Flood Advisory: Be Aware: An Flood Advisory is issued when a specific weather event that is forecast to occur may become a nuisance. A Flood Advisory is issued when flooding is not expected to be bad enough to issue a warning. However, it may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may threaten life and/or property.
Flood Watch: Be Prepared:A Flood Watch is issued when conditions are favorable for a specific hazardous weather event to occur. A Flood Watch is issued when conditions are favorable for flooding. It does not mean flooding will occur, but it is possible.
Flood Warning: Take Action! A Flood Warning is issued when the hazardous weather event is imminent or already happening. A Flood Warning is issued when flooding is imminent or occurring.
Flash Flood Warning: Take Action! A Flash Flood Warning is issued when a flash flood is imminent or occurring. If you are in a flood prone area move immediately to high ground. A flash flood is a sudden violent flood that can take from minutes to hours to develop. It is even possible to experience a flash flood in areas not immediately receiving rain.
Before a Flood
- Communicate with family who will be the contact person will be a safe location meet.
- Develop an emergency kit. Have enough food, water and medications to last at least 3 days per person. Have battery powered flashlights, rubber boots, first-aid kit, rubber gloves and battery powered radio.
- Is your home or business in a floodplain? How about roads to escape the flood plain? What is the fastest way to get to higher ground?
- If you have access to sandbags or other materials, use this to protect your home or business.
- Make sure your sump pump is in good working order.
- Have a plumber add check valves to prevent water from backing up into your drains.
- Have your circuit breaker panel marked clearly for the sections in your home.
- Purchase flood insurance if possible. This has do be done before there is a threat of flooding and policies can take up to 30 days to go in effect.
- Don't wait until the last minute to gather items for your family and pets. You may have to be evacuated.
- Make sure your cell phones and portable radios are all charged to full capacity.
- If flooding is likely at your home, don't wait to be ordered to leave, evacuate yourself. Take your pets with you and make plans to stay at an alternative place.
During a Flood
- During a flood, water flow and levels can vary. Stay up to date on local weather forecasts and stay out of flood waters at all costs. Evacuate when you see water levels getting high. Don't wait until it is too late!
- If you are told to evacuate, do so immediately! Lock your house and take your pets with you. If there is time, disconnect utilities.
- Do not enter a basement or any room where water is covering electrical cords or outlets.
- If you see sparks, hear buzzing or popping, stay out of the water! It may have electricity in it.
- Avoid flood waters at all costs! It only takes 6 inches to knock you off your feet. If you are trapped by moving flood water, move to the highest ground and call or yell for help.
- Do not drive in flood waters! TURN AROUND - DON'T DROWN! 12 inches of water can move a car or small SUV and 18 inches can move a truck. The road may also be washed out below.
After a Flood
- Stay tuned to your local news for updated information on road conditions and water levels. Be sure it is safe to drink, cook or clean with water.
- Standing water hides many dangers such as chemicals, toxins and diseases. Avoid it at all costs.
- Do not visit disaster areas, you may hamper rescue efforts.
- Roads are closed to keep you safe, pay attention and respect the signs.
- Do not enter flood damaged homes or buildings unless you are told it is safe to do so. Contact your insurance agent as soon as you can.
- Contact family members and friends to let your know your safe. Register with the American Red Cross "Safe and Well" website for friends and family to know you are safe.
What is the difference between a Flood Watch and a Flood Warning issued by the National Weather Service?
Flood Advisory: Be Aware: An Flood Advisory is issued when a specific weather event that is forecast to occur may become a nuisance. A Flood Advisory is issued when flooding is not expected to be bad enough to issue a warning. However, it may cause significant inconvenience, and if caution is not exercised, it could lead to situations that may threaten life and/or property.
Flood Watch: Be Prepared:A Flood Watch is issued when conditions are favorable for a specific hazardous weather event to occur. A Flood Watch is issued when conditions are favorable for flooding. It does not mean flooding will occur, but it is possible.
Flood Warning: Take Action! A Flood Warning is issued when the hazardous weather event is imminent or already happening. A Flood Warning is issued when flooding is imminent or occurring.
Flash Flood Warning: Take Action! A Flash Flood Warning is issued when a flash flood is imminent or occurring. If you are in a flood prone area move immediately to high ground. A flash flood is a sudden violent flood that can take from minutes to hours to develop. It is even possible to experience a flash flood in areas not immediately receiving rain.
Before a Flood
- Communicate with family who will be the contact person will be a safe location meet.
- Develop an emergency kit. Have enough food, water and medications to last at least 3 days per person. Have battery powered flashlights, rubber boots, first-aid kit, rubber gloves and battery powered radio.
- Is your home or business in a floodplain? How about roads to escape the flood plain? What is the fastest way to get to higher ground?
- If you have access to sandbags or other materials, use this to protect your home or business.
- Make sure your sump pump is in good working order.
- Have a plumber add check valves to prevent water from backing up into your drains.
- Have your circuit breaker panel marked clearly for the sections in your home.
- Purchase flood insurance if possible. This has do be done before there is a threat of flooding and policies can take up to 30 days to go in effect.
- Don't wait until the last minute to gather items for your family and pets. You may have to be evacuated.
- Make sure your cell phones and portable radios are all charged to full capacity.
- If flooding is likely at your home, don't wait to be ordered to leave, evacuate yourself. Take your pets with you and make plans to stay at an alternative place.
During a Flood
- During a flood, water flow and levels can vary. Stay up to date on local weather forecasts and stay out of flood waters at all costs. Evacuate when you see water levels getting high. Don't wait until it is too late!
- If you are told to evacuate, do so immediately! Lock your house and take your pets with you. If there is time, disconnect utilities.
- Do not enter a basement or any room where water is covering electrical cords or outlets.
- If you see sparks, hear buzzing or popping, stay out of the water! It may have electricity in it.
- Avoid flood waters at all costs! It only takes 6 inches to knock you off your feet. If you are trapped by moving flood water, move to the highest ground and call or yell for help.
- Do not drive in flood waters! TURN AROUND - DON'T DROWN! 12 inches of water can move a car or small SUV and 18 inches can move a truck. The road may also be washed out below.
After a Flood
- Stay tuned to your local news for updated information on road conditions and water levels. Be sure it is safe to drink, cook or clean with water.
- Standing water hides many dangers such as chemicals, toxins and diseases. Avoid it at all costs.
- Do not visit disaster areas, you may hamper rescue efforts.
- Roads are closed to keep you safe, pay attention and respect the signs.
- Do not enter flood damaged homes or buildings unless you are told it is safe to do so. Contact your insurance agent as soon as you can.
- Contact family members and friends to let your know your safe. Register with the American Red Cross "Safe and Well" website for friends and family to know you are safe.
FLASH FLOOD
Flash floods are exactly what the name suggests: floods that happen in a flash! Flash floods generally develop within 6 hours of the immediate cause. Causes of flash flooding include heavy rain, ice or debris jams, and levee or dam failure. These floods exhibit a rapid rise of water over low-lying areas. In some cases, flooding may even occur well away from where heavy rain initially fell. This is especially common in the western United States where low lying areas may be very dry one minute, and filled with rushing water from upstream the next.
There are many reasons that flash floods occur, but one of the most common is the result of copious amounts of rainfall from thunderstorms that cause flash flooding. This can also occur when slow-moving or multiple thunderstorms move over the same area. These sudden downpours can rapidly change the water levels in a stream or creek and turn small waterways into violent, raging rivers. Urban areas are especially prone to flash floods due to the large amounts of concrete and asphalt surfaces that do not allow water to penetrate into the soil easily.
Steep, hilly, or mountainous terrain produces rapid runoff and quick stream response, since the water will travel downhill at greater speeds into rivers and over land. Rocky terrain can exacerbate the development of flash floods and raging waters since rocks and clay soils do not allow as much water to infiltrate the ground. Steep, narrow valleys generate rapidly flowing waters that can quickly rise to considerable depth. For instance, a mountain creek that is usually only 6 inches deep can swell to a 10-foot depth in less than one hour.
SNOWMELT
Snowmelt flooding occurs when the major source of water involved in a flood is caused by melting snow. The northern tier states and mountainous areas of the U.S. are particularly susceptible to snowmelt flooding. Unlike rainfall that can reach the soil almost immediately, the snowpack can store the water for an extended amount of time until temperatures rise above freezing and the snow melts. This frozen storage delays the arrival of water to the soil for days, weeks, or even months. Once it begins to melt and does reach the soil, water from snowmelt behaves much as it would if it had come from rain instead of snow by either infiltrating into the soil, running off, or both. Flooding can occur when there is more water than the soil can absorb or can be contained in storage capacities in the soil, rivers, lakes and reservoirs.
High soil moisture conditions prior to snowmelt can contribute to snowmelt flooding. Rainfall during the late fall is particularly important because there is less evapotranspiration and less time for the soil to drain and dry before it freezes. Ground frost or frozen soil is another contributor. Deep, hard ground frost prevents snowmelt from infiltrating into the soil. Cold temperatures prior to heavy snowfall and normal or above normal soil moisture contribute to this.
Deep snow cover can worsen snowmelt flooding since there is more water stored and available for snowmelt. Also, when snow cover is widespread, it usually keeps air temperatures cooler and delays spring warming, which increases the potential for more rapid snowmelt. Rain falling while snow is still on the ground contributes more water for flooding and helps to melt the snowpack, thus rain-on-snow events are watched carefully.
Most often, snowmelt is a relatively slow phenomenon. Snowmelt rates are usually comparable to light or moderate rainfall. Important exceptions to this can occur, especially during unusually warm periods with high dew point temperatures, and when nighttime temperatures remain above freezing. Snowmelt rates can be much higher than normal under these conditions, which can increase the risk of snowmelt flooding.
Flash floods are exactly what the name suggests: floods that happen in a flash! Flash floods generally develop within 6 hours of the immediate cause. Causes of flash flooding include heavy rain, ice or debris jams, and levee or dam failure. These floods exhibit a rapid rise of water over low-lying areas. In some cases, flooding may even occur well away from where heavy rain initially fell. This is especially common in the western United States where low lying areas may be very dry one minute, and filled with rushing water from upstream the next.
There are many reasons that flash floods occur, but one of the most common is the result of copious amounts of rainfall from thunderstorms that cause flash flooding. This can also occur when slow-moving or multiple thunderstorms move over the same area. These sudden downpours can rapidly change the water levels in a stream or creek and turn small waterways into violent, raging rivers. Urban areas are especially prone to flash floods due to the large amounts of concrete and asphalt surfaces that do not allow water to penetrate into the soil easily.
Steep, hilly, or mountainous terrain produces rapid runoff and quick stream response, since the water will travel downhill at greater speeds into rivers and over land. Rocky terrain can exacerbate the development of flash floods and raging waters since rocks and clay soils do not allow as much water to infiltrate the ground. Steep, narrow valleys generate rapidly flowing waters that can quickly rise to considerable depth. For instance, a mountain creek that is usually only 6 inches deep can swell to a 10-foot depth in less than one hour.
SNOWMELT
Snowmelt flooding occurs when the major source of water involved in a flood is caused by melting snow. The northern tier states and mountainous areas of the U.S. are particularly susceptible to snowmelt flooding. Unlike rainfall that can reach the soil almost immediately, the snowpack can store the water for an extended amount of time until temperatures rise above freezing and the snow melts. This frozen storage delays the arrival of water to the soil for days, weeks, or even months. Once it begins to melt and does reach the soil, water from snowmelt behaves much as it would if it had come from rain instead of snow by either infiltrating into the soil, running off, or both. Flooding can occur when there is more water than the soil can absorb or can be contained in storage capacities in the soil, rivers, lakes and reservoirs.
High soil moisture conditions prior to snowmelt can contribute to snowmelt flooding. Rainfall during the late fall is particularly important because there is less evapotranspiration and less time for the soil to drain and dry before it freezes. Ground frost or frozen soil is another contributor. Deep, hard ground frost prevents snowmelt from infiltrating into the soil. Cold temperatures prior to heavy snowfall and normal or above normal soil moisture contribute to this.
Deep snow cover can worsen snowmelt flooding since there is more water stored and available for snowmelt. Also, when snow cover is widespread, it usually keeps air temperatures cooler and delays spring warming, which increases the potential for more rapid snowmelt. Rain falling while snow is still on the ground contributes more water for flooding and helps to melt the snowpack, thus rain-on-snow events are watched carefully.
Most often, snowmelt is a relatively slow phenomenon. Snowmelt rates are usually comparable to light or moderate rainfall. Important exceptions to this can occur, especially during unusually warm periods with high dew point temperatures, and when nighttime temperatures remain above freezing. Snowmelt rates can be much higher than normal under these conditions, which can increase the risk of snowmelt flooding.