Flash floods are fatal, but before delving into a flash flood warning what to do, it’s important to understand what a flash flood is.
Flash floods are sudden and violent floods caused by heavy rains, dam breaks, or both.
Flash flood warnings are weather statements issued by national weather forecasting agencies worldwide to alert the public that a flash flood is imminent in a specific area. The main factors contributing to the likelihood of a flash flood are rainfall intensity and duration, soil condition, ground cover and topography.
Understanding Contents of a Flash Flood Warning
The National Weather Service issues flash flood warnings as it gauges potential flash-flooding in areas that have been affected by a previous watch.
When flash flood warnings are declared, the media is alerted to prepare for possible coverage.
Media outlets can also run approved tips on how viewers can prepare for high waters.
Flash floods normally occur a few hours after sudden water releases from dams or levees or following rainstorms that cause ice or debris dams to collapse.
Fact: The average number of flood-related deaths per year in the United States is higher than any hazardous weather-related fatalities.
Predicting Flash Floods
To predict the possibility of a flash flood and send out a flash flood warning, meteorologists need to know where storms are carrying intense amounts of precipitation.
Rainfall of greater than 3 inches per hour over a large area, usually caused by thunderstorm activity, can lead to flash flooding.
Here are other criteria for flash flood prediction:
- How much rainfall
- How quick is the downpour
- Soil saturation
Radar instruments on the ground or in aircraft measure the height of water levels and transmit this information to a central office via phone lines, radio waves, or satellites.
However, radar can provide accurate information about rainfall only up to a certain distance. It may also be limited in mountainous areas because nearby hills and mountains can distort the signal.
Land Topography and Flash Floods
Researchers at the National Center for Atmospheric Research are now considering the impact of land features when predicting flash floods.
In addition to such information, topographical information also allows them to make more accurate predictions about how a given location will handle a certain amount of water.
It is tricky to measure the amount of moisture in the soil as it happens invisibly under our feet. NASA has been exploring remotely measuring soil moisture over areas larger than those currently monitored by rain gauges.
Fact: Satellite data also helps assess the topography of various places to issue accurate flash flood warnings.
What to Do During a Flash Flood Warning?
After a flash flood warning what to do? Here are the main steps to undertake when you get a flash flood warning:
1. Stay Informed
Keep a radio near you or turn on the television. National Oceanic and Atmospheric Administration (NOAA) Weather Radio alerts you to disasters and other emergencies.
Local TV and radio stations may also provide information specific to local areas.
2. Be Alert
Flash flooding can occur without warning. If you’re wondering about flash flood warning, what does it mean?
The idea is that you ensure you and your family are ready to take the measures required for your safety.
It would be best to alert you to signs of possible floodings, such as rainwater pooling on street surfaces or stream swelling.
3. Move to Higher Ground
If there is a risk of flooding in your area, consider moving to higher ground or sheltering with family or friends until the danger passes.
Remember to only take the most important items with you—for example, those that could help you survive if you become stranded or have to leave your home in a hurry.
4. Follow Instructions
When disaster strikes, rely on your local authorities for various information and services.
They are the most informed about affected areas, will best be able to tell you where to stay away from, and are likely to need your assistance as well.
5. Be Proactive
If you live along a river, like the Mississippi, or another area subject to flash flooding, you should realize that floods can cut off your access to safe areas.
To ensure that you get out of bed and to safety immediately if warned of an evacuation, be sure to have a plan in place that alerts you to the danger of flash flooding.
Note: If a flash flood watch is issued for your area, you should be prepared to move within 2 hours; for flash flood warnings, evacuate immediately.
6. Beware of Evacuation Routes
Be prepared. Evacuation routes are usually well marked by yellow or orange signs.
If you need to get out of a flood zone, obey recommendations or risk being stuck or electrocuted on a damaged road or bridge.
7. Leave Early
Because heavy rains can cause flooding that forces road closures, it is vital to allow yourself enough time to reach your destination before nightfall. Without proper preparation, you may find yourself stuck due to blocked routes.
8. Other Precautions
Perhaps the most important what to do if flash flood warning is to ensure you don’t drive.
If you must drive during a flood, heed all posted warning signs. Never drive through moving water. Never attempt to cross a flooded road if you cannot see the roadbed.
Fact: During flash floods, water depth is not always too obvious.
Sometimes under intense flash floods, roadbeds may be washed away, making you trapped or stranded.
When a barrier is set up around a flooded area by police or other authorities, it is for your safety. Flood waters can be deceptive; they can look like calm pools of water at night.
Obey the Six Inch Rule
When the stream you are crossing becomes too deep, turn around and don’t drown. Six inches of swift-moving water can knock you off your feet.
A safe rule of thumb is to assume that any stream with a flow over 6 inches a second is too dangerous to cross. Many people are swept away wading through floodwaters, resulting in injury or death.
Children should never play around high water, storm drains, or viaducts. Fast-moving water can sweep even adults away, let alone children.
If You live in Frequent Flood Area?
If you live in an area that frequently gets flash-floods, follow these rules:
1. Store Clean Water
You can store clean water in plastic bottles, sinks and bathtubs, in case of abrupt service interruption or contamination.
2. Bring All Things Outside
Bring all things outside—patio furniture, lawn ornaments, etc.—inside. You might have to move them again, but it is a better idea than leaving them outside and worried about them washing away.
3. Move Valuables to Top Floor
If you live in a flood zone, move the household valuables to the top floor of your home, if possible. Moving these items to higher floors will reduce damage should floodwaters affect your home.
4. Turn Off Utilities Switches
It’s best if you turn off all utilities at the main power switch. Ensure the gas valve is also closed. Turning off utilities helps prevent extensive damage to homes in the area.
5. Emergency Supply Kit
Prepare an emergency supply kit and make a family emergency plan that includes an evacuation plan. Include a first aid kit, cash, and extra clothing. A three-day supply of food and water per person is recommended.
6. Fill Up Your Car’s Tank
In case of evacuation order during a flash flood, fill up your car’s tank if your destination is inaccessible by public transit.
If the power goes out and the stations are closed for many days, you will have fuel available to use a generator or, if necessary, to evacuate.
In many flash floods, floodwater causes death by drowning. If you are in a flood situation and have time, prepare for flooding by gathering supplies and filling containers with water.
During a flash flood, move away from floodwaters and toward higher ground.
It’s not enough to focus on flash flood warning what to do since what you do after the flash flood is equally important.
After the flood, follow appropriate procedures to protect your health and that of your loved ones. You might lose property or a few possessions to flash floods but always remember your health is much more important.