by Joe Alton, MD of www.doomandbloom.net, co-author of The Survival Medicine Handbook
There’s a lot of information on the risks associated with storms, hurricanes, and tornadoes, but not as much about their consequences. Just about any storm can cause flooding, and many communities are not prepared to deal with it. As a result, water supplies are contaminated, emergency services are crippled, and important infrastructure can fail.
In Texas and Oklahoma, heavy rains caused major damage and a number of deaths, with more precipitation expected. Floods are not a rare occurrence, with a number of major disasters over the past few years: In 2013, Boulder, Colorado experienced 6 months of rainfall over the span of a week. Flooding in the wake of Hurricane Katrina (2005) was severe enough to cause a humanitarian crisis.
To respond appropriately to a flood, we should understand the various types of flooding and the steps we can take to stay safe.
What is a Flood?
A flood is defined as an overflow of water that submerges land which is normally dry. Flooding may occur from water bodies, such as a seacoast, river, or lake. The water overcomes levees, resulting in the inundation of populated areas. It may also occur due to an accumulation of rainwater on saturated ground.
Some floods develop slowly, while others (called flash floods), can develop in a very short time and rush into areas where it wasn’t even raining. As a result, flash floods often catch the population downriver by surprise, causing severe damage and loss of life.
Types of Floods
There are several types of floods:
Floods can happen on flat or low-lying areas when the ground is saturated and water cannot run off quickly enough to prevent accumulation. Floods related to rainfall can also occur if waterfalls on an impenetrable surface, such as concrete, asphalt paving or frozen ground, and cannot rapidly be absorbed. In urban areas, it usually takes at least 1 inch (25 mm) of rainfall per hour to create significant ponding of water on hard surfaces.
Floods happen in rivers when the flow rate exceeds the capacity of the river channel. This happens particularly at bends in the waterway. The faster the flow rate, the more dangerous it is; people traditionally live and work by rivers due to access to fertile soil and trade routes.
Flooding on the coast is commonly caused by a combination of tidal surges caused by winds and low barometric pressure. Coastal areas may be flooded by storm events, such as hurricanes, resulting in waves over-topping seawalls and levees.
Failures of vital infrastructures, such as the collapse of a dam, may cause catastrophic flooding,. This exact event occurred in Johnstown, Pennsylvania in 1889, costing 2,200 lives. Major flooding may also be caused by the effects of an earthquake or volcanic eruption. These events often occur at sea hundreds of miles from the area affected, but result in tidal wave floods called Tsunamis.
Most people have heard of hurricane or tornado watches and warnings, but the U.S. weather service also tries to warn the populace of flooding. In order of imminent danger, they are:
• Flood Advisory: Flood advisories are issued when an expected weather event may cause some flooding, but not enough to be a major issue. Significant inconvenience may be possible and lead to dangerous situations if caution isn’t exercised.
• Flood Watch: Flood watches are issued when weather conditions become favorable to cause significant flooding. Although flood conditions are not imminent, steps should be taken to prepare for such an event.
• Flood or Flash Flood Warning: Flash flood or flood warnings are issued when hazardous flooding is imminent or has already begun. Action should be taken to avoid life-threatening situations.
Many people ignore these warnings at their own peril. If you live in a low-lying area, especially near a dam or river, then you should closely monitor and heed warnings when they are given and be prepared to evacuate quickly. Rising flood waters could easily trap you in your home.
Preparing for Floods
If you live in a floodplain, you should:
• Build an emergency kit with food, water (yes, water), and medical supplies.
• Have a way to communicate with family members.
• Elevate the furnace, water heater and electric panel
• Install special “check valves” to prevent water from backing up into the drains of your home.
• Consider having materials to make waterproof barriers to stop floodwater from coming into the building
• Seal walls in basements
When It Happens
You can’t stop the rain from falling and you can’t stop the tide from coming in, but you can weather the effects of flooding with some sound strategy and a little preparation. Here are some flood safety tips:
Get Out Early
Make the decision to leave for higher ground before extensive flooding occurs. Closely monitor public service announcements for warnings and advice from experts.
Be Careful Walking Through Flowing Water
Drowning is the most common cause of death during a flood, especially a flash flood. Rapidly-moving water can knock you off your feet even if less than a foot deep.
Don’t Drive Through a Flooded Area
As many people drown in their cars as anywhere else. Cars stall and roads/bridges could easily be washed out. Try to figure out now if there is a “high road” to safety before a flood occurs.
Beware Of Downed Power Lines
Electrical current is easily conducted through water. Watch for downed power lines; you don’t have to touch them to be electrocuted; just stepping in the water they’re in could kill you.
Turn Off The Power
If you have reason to believe that water will get into your home, turn off the electricity. Don’t use appliances or motors that have gotten wet unless they have completely dried. You might have to take some apart to clean debris out of them.
Watch Out For Intruders
Critters that have been flooded out of their homes may seek shelter in yours. Snakes, raccoons, and other unfriendly creatures may decide your home is now their territory. Human intruders may be interested in your property, as well.
Look Before You Step
After a flood, watch where you step; there is debris everywhere. The floors of your home may be covered in mud, causing a slip-and-fall hazard. There may be damage to foundations of flooded buildings, even if the water has subsided.
Check for Gas Leaks
Don’t use candles, lanterns, stoves, or lighters unless you are sure that the gas has been turned off and the area has been well-ventilated.
Exhaust Fumes Can Kill
Only use generators, camping stoves or charcoal grills outside. You can easily be overcome by the fumes they emit.
Clean Out Saturated Items Completely
Floodwaters are not clean! Don’t use floodwater as drinking water or to cook food unless you have thoroughly sterilized and filtered it. Make sure you have food storage in waterproof containers.
More Flood Preparedness Tips
by Paul North
Although it may not be the apocalypse, flooding is a serious threat to many areas of the world. Floods can come unexpectedly and wreak havoc quickly so it is important to be as well prepared as possible for them.
They can just as easily be caused by adverse weather conditions, such as the floods in the UK over the last couple of years, or unexpected accidents such as a burst dam. But how do you prepare for the unexpected?
Research your area
Whether it is somewhere you already live, and especially if it is somewhere you are potentially considering moving to, researching the potential flood conditions of an area are essential to determine how at risk you could be.
In the UK you can obtain the flood history of any property from the Environment Agency for free (unless the report takes over 18 hours to put together when there is a small fee associated with it). In the US you can check if your home is near a floodplain by accessing FEMA’s Flood Map Service Centre.
This is particularly useful if you are researching land to build a property on, and you can check as many different areas as you need to.
Have a plan
This may sound obvious but a lot of people who live in high flood risk areas accept this, and yet have no plan in place should the worst happen. Having a carefully considered plan can save you time and money in the event of a flood if you implement it quickly enough to alleviate any damage, or at least of the worst of it.
Sandbags are often used to block doors and create a barrier against floodwater. The best time to get your sandbags is, of course, before a flood has hit so make sure you have a supply of these ready to be used.
You will be able to respond quicker, resulting in less damage, if you have these at hand straight away. If you do not have any sandbags they can be made from old clothes and bed sheets and filled with gravel or even dirt if that is all that is available.
If preventing the flood damage is not possible you should also have prepared to leave your property as quickly as you can, taking important possessions with you. This means having a bag of essentials prepared so you can leave quickly, as well as knowing where anything is that you may want to take with you on short notice and ensuring it is somewhere that can be easily reached as you leave. Remember that you may need to be away from home for days, or even week depending on how bad the damage is.
It is also important to plan and prepare for staying in your home in certain conditions. A flood may wipe out your water and electricity supply, even if the water itself doesn’t reach you. Having a well thought out stock of candles, lamps, drinking water and other supplies could make all the difference between continuing to live comfortably or having to leave your home.
It is also important to have a supply of food in case you are stuck for any period of time. Tinned food is the best as it is not susceptible to flood damage like fresh food and can be kept and stored for long periods of time.
As well as the obvious such as food and drinking water, there are several items that will make your life much easier if trapped in a flood. These include waterproof clothes, which will keep you comfortable and dry and waterproof containers for electrical items such as your mobile phones and torches. Torches are of course another essential item, as well as a small kit of medical supplies.
Most homes will have a basic first aid kit but it worth keeping on top of this and making sure this is always well stocked and ready to be used. If anyone in the house takes regular medication that they cannot do without then you should also ensure there is always a good supply of this in the house.
All items, where possible, should be stored on the upper floor of the house as high as possible, in order to keep them away from any potential flood damage.
Whilst most people tend to be sensible enough to take out insurance for their home and contents, a lot of insurance policies do not cover floods. Instead of getting caught out, take the time to research your policy and if flood damage is not covered invest in a separate flood insurance policy too.
Although you may not want to spend the extra money if a flood does affect you then you could end up spending far more if you are not covered by a suitable policy. Having insurance in place will make your life easier during what is bound to be a stressful time.
As well as preparing for all eventualities of a flood you should prepare for the cleanup afterward. Cleaning after a flood can be complicated. To begin with, you may need to remove any loose dirt, rocks and other debris from your home.
It can be muddy where the water has been and anything touched by the mud is contaminated and should be cleaned thoroughly or disposed of if this is not possible. Anything that can be salvaged should be cleaned and dried, making sure no trace of the floodwater remains.
You will need to disinfect all surfaces so a good supply of bleach for this is essential, and any rugs, carpets or soft furnishings that have been damaged will probably need to be thrown out. No electricity should be used until it has been checked by a professional, and the foundations should be thoroughly checked for cracks and signs of any long-term damage that may cause problems further down the line.