- 1 Types of Floods
- 2 Am I at risk of flooding?
- 3 When is flooding likely to occur?
- 4 How long will flood waters stay around?
- 5 Flood Watches and Flood Warnings
- 6 How to Prepare for a Flood
- 7 Using Sandbags to Redirect and Divert Flood Water
- 8 Precautions to Take During the Flood
- 9 Lessons Learned From Hurricane Katrina and Sandy
How to Prepare for a Flood
Preparing for a flood is extremely important. Flooding is one of the most common natural disasters in the United States (and in many other parts of the world). It occurs across the country, but those that live in areas that are lower in elevation than a nearby body of water (streams, lakes, oceans, etc.) are especially at risk. Knowing how to prepare for a flood can save you and your family.
In fact, flooding can be so dangerous, that it is one of the few disasters that I suggest bugging out for.
Floods kill more people in the United States every year than lightning, hurricanes or tornadoes. They also cause roughly $5 billion a year in damages. This is due, in part, to complacency by those in flood areas. Water is just not all that intimidating compared to other types of disasters.
Flooding can occur in a number of ways. The most common ways are when the ground in an area cannot absorb rain or melting snow, strong winds push seawater inland during a storm, when a waterway is blocked by ice and debris or when a man-made structure like a dam or sewer breaks.
Types of Floods
Inland flooding normally occurs during periods of extended rainfall or when dams and levees fail. The ground cannot absorb the water fast enough resulting in flooding.
Flash floods are the most dangerous type of flood and can occur with no warning at all. They are the number one cause of weather-related deaths. They occur when water quickly fills normally dry streams and river beds or when storm drains become overwhelmed.
Areas affected by wildfires can contribute to flash flooding. Once the vegetation is burned off of an area, rainwater can flow quickly downhill sides and mountains into areas of lower elevation.
Flash flooding in canyons is another possibility. Heavy rainfall can quickly fill the canyon floor causing what can only be described as rapids for miles down the canyon.
Urban areas struck by flash flooding are especially at risk as they are normally covered in either concrete or asphalt, preventing flood waters from being absorbed. Runoff from buildings only compounds the effect. This channels the water over roadways and sidewalks and into low areas like underpasses, subway tunnels, parking structures and basements.
If you are in an urban area that can experience flash flooding, DO NOT seek shelter in these areas. You could easily become trapped and drown.
River flooding normally accompanies long periods of heavy rainfall causing water levels to rise over the top of the river bank. Severe tropical storms can cause river flooding in a relatively short period of time. Melting snow and ice can increase the chances of a river flood.
Floods along the coast are caused by a combination of storm surge (rising water levels caused by high winds) and heavy rainfall. If these are combined with a high tide, water levels can get especially high. Look at the pictures of the after effects of Hurricane Katrina for an example of the possible destructive power of storm surge.
As we saw with hurricane Irma, the storm surge can be the most disastrous potion of many major storms.
This video from FEMA explains storm surge in more detail.
Am I at risk of flooding?
For those in the United States, FEMA has a website at FloodSmart.gov that is designed to help you evaluate your overall flood risk. Unfortunately, it is currently down and redirects you to the national flood insurance program page.
Once FloodSmart.gov is back up, it should provide better info than what is currently provided on the flood insurance page.
For the time being, you can use their interactive flood map. It allows you to see the number of occurrences of floods by state and further breaks it down by county.
There is also a printable flood map available. It allows you to type in your address or Lat/Long coordinates to get a printable flood map of your area. This would be good to have pre-printed and stored along with any other plans you may have.
Say what you want about FEMA, but their site has a ton of useful prepping information on it if you’re willing to dig far enough.
Even if you are not at risk of flooding where you are now, make sure you take the threat of flooding into account for any bug out location you may have planned as well as along the route you will likely have to take to get there.
When is flooding likely to occur?
Trying to predict floods is difficult unless you understand the risks associated with your area.
For the United States, June to November are considered hurricane season. This puts the coasts at higher risk during those times. Heavy rain puts the Midwest at risk in the summer, and the Southwest is at risk during the later summer. The Northeast and Northwest are at a higher risk in the spring when melting snow will add to any rainfall.
How long will flood waters stay around?
The length of time that flood waters will stay in an area will vary depending on the severity of the flood and the environmental conditions.
FEMA quotes times from 4-8 hours with longer times being common. In the end, it’s all going to come down to the severity of the flooding. Flooding following Katrina lasted for weeks.
Flood Watches and Flood Warnings
A flood watch occurs when the conditions are right for a flood to occur. A flood warning is issued when flooding is occurring or it’s about to start.
How to Prepare for a Flood
I’m going to cover preparing for a flood in a modern “grid-up” environment. If you were preparing for a flood in a grid-down situation, many of these steps would be the same. The ones that wouldn’t apply, like getting insurance, will be pretty obvious.
If you are in a flood-prone area, I’d suggest getting flood insurance policy. You probably have to have it anyway, and on the off chance that your home gets damaged by a flood you’re going to want it. Think of insurance as just another prep. You have food and water just in case something bad happens…you get insurance for the same reason.
It takes about 30 days for flood insurance to kick in. Plan accordingly!
The best way to protect yourself from a flood is to leave the area if it’s at all possible. Before you go anywhere, make sure you prepare your house by doing the following:
- Let local authorities know that you are moving to a safer place if you have time. This will prevent them from searching for you if there is a need for recovery operations following the flood.
- Move valuable items and electronics to higher areas. Put them on the second floor, beds, countertops, etc.
- Use a waterproof container or bag to store any vital documents and medical supplies.
- Take your animals with you. If you can’t, then you need to make sure they have food and water and are in the safest place that you can put them.
- Leave the doors to your refrigerators and freezers open. This will help to prevent them from floating around and causing damage to your house.
- Turn off electricity, water, and gas to your home.
- Put sandbags in your toilets and over and drains in the laundry room or bathroom. This will keep sewage from backing up into your home. (Do this even if you plan on staying during the flood.)
Using Sandbags to Redirect and Divert Flood Water
I’m not going to insult anyone’s intelligence by going super in depth about sandbags. These are just some tips and best practices for flood water and general sandbag use.
Use bags around 14-18” wide and about 30-36” deep. Any purpose made sandbag will be around this size.
Fill them roughly ½ way. This makes them easy to move and set into place. It also makes them moldable enough to get a tight seal.
Don’t bother tying the bags unless you plan on storing them. It’s best to set up close to the area you’re trying to protect. Fill a bag then just lay it in place with the opening folded under itself to keep the flap closed.
Interlock the sandbags as you stack them and place the flap in the direction you think the water will be coming from. This will help to keep the bags closed in the water flow.
You can improvise a sandbag filling station with a couple 2x4s and a traffic cone or even a ladder as you can see in the picture below. There is no need for expensive, single-purpose sandbag filling contraptions.
(and I did it anyway…200 words about sandbags…)
Precautions to Take During the Flood
Only walk or drive through flood waters as a last resort. Six inches of moving water can knock a person over and one foot of moving water is enough to sweep away a vehicle.
Flood water is often contaminated with sewage and can spread diseases. You can read more about waterborne diseases in this article. Try to keep anything that touches flood water away from your mouth, nose, and eyes. Coming in contact with feces-contaminated water is one of the main ways that waterborne pathogens are spread.
Even if you have a jacked up pick-up or SUV, it’s recommended not to drive into the water. You have no idea what is under the surface and moving water can quickly erode walkways and roads.
There is a possibility that live underground or downed power lines are in standing water.
If flood water rises around your vehicle but is not moving, you should attempt to get to safety. You should not try to escape into running water.
Lessons Learned From Hurricane Katrina and Sandy
Hurricane Katrina and Sandy were not simply floods, they obviously had high winds associated with the damage they caused, but a vast amount of damage was caused by the flooding that accompanied them. This allows us to look at them and take away some lessons learned. We should always strive to learn from disasters.
Large-scale flooding that took place during Katrina and Sandy leaves TONS (as in weight) of debris behind. That needs to be taken into consideration when you finally come home or as you recover from home.
A sump-pump, or another way to remove the standing water in your home, may be needed when you finally make your way back home to begin recovering.
Communication channels cannot handle the sheer volume of people all trying to communicate at once when a large-scale disaster happens in a densely populated area. Other means of communication become important. Twitter was used extensively by survivors of Sandy. Be creative and think outside of the box when it comes to making contact with loved ones.
Even when the government is in power and able to direct recovery operations following an event, they can still easily be overwhelmed.
You need to be prepared for martial law or some other kind of enhanced rule of law following large-scale natural disasters.
Fuel and just in time food delivery could be interrupted for weeks. The same goes for disruptions to electrical and water services. To better prepare for long-term flooding, you can stock clean water and non-perishable food items beforehand. This can be as simple as having several days worth of bottled water and canned food stored in the back of a closet.
Evacuating to a government-run camp is a “use at your own risk” proposition. Just read this one story following Hurricane Katrina.
There are far more reasons to be prepared than people like to admit.
Our other Emergency Preparedness articles look at a wide range of disaster prepping scenarios. Go check them out.