Hurricane Matthew in October 2016 flooded homes across Virginia, and many of the roughly 2,000 homes flooded statewide were outside the mapped floodplain, according to Virginia Emergency Management. The lesson for a homeowner is that a flood map shows only part of the risk, and that water can reach a house by many routes that the map does not show.
Key takeaways
- Many of the roughly 2,000 Virginia homes flooded in Matthew were outside the mapped floodplain, according to Virginia Emergency Management.
- Flood maps are planning tools and do not describe every route water can take into a house.
- Storm drains, saturated ground, garage openings and low thresholds can bring water into a house outside a mapped zone.
- Forecasts give an average rainfall, and a single house can take more water than the average.
- The readings from a crew, and the homeowner's own photographs, are the most reliable record of what happened to a particular house.
What did Hurricane Matthew do to Virginia's homes?
Hurricane Matthew brought heavy rain and flooding to Virginia in October 2016, and Hampton Roads felt more impact than the forecast had expected. Many homes were flooded, and the flooding was not confined to the places the flood maps had marked as high risk.
Water ran off the land into drains, streets and low ground, and it reached houses by routes that were not always the ones the maps had anticipated.
In Suffolk, the flooding included homes on Gates Road, where one resident reported water more than six feet deep, and a creek downtown that crossed a road and swept a car away. Those events show that water in a single storm can move in several directions, and that the damage is not limited to the river's edge.
What does "outside the mapped floodplain" actually mean?
It means that a house was not inside the area a flood map shows as at high risk for a given storm or source. Such a house can still flood, because the map is drawn from models and does not capture every drain, street, slope or low opening.
A floodplain map shows where water is expected to rise in certain conditions. It is useful for planning, and it is a guide to likely risk, but it is not a guarantee in either direction. A house outside the line can flood, and a house inside it may never see water.
The gap between the map and the ground is most visible in heavy storms, when drains are full and the ground cannot take more water. The map does not follow the water into the streets and the yards, and that is where many homes outside the mapped zones were reached.
How did the water get into homes outside the map?
The usual routes were storm drains that backed up, saturated yards that drained toward the foundation, garages with low thresholds and crawl space vents. Each of these can bring water into a house whatever the map shows.
A storm drain that cannot take the rain can push water back up through a yard drain or a floor drain. A yard that slopes toward a house can deliver a steady flow to the foundation, and a garage floor that is lower than the street can take water through its door.
Crawl spaces are a common point of entry, because their vents are close to the ground. Once water is inside a crawl space it can wet the joists and the subfloor long before the floor above shows any sign, and the water can then spread through the house.
Why a forecast is not a measure of what a house will take
A forecast gives an average rainfall across an area, and it cannot say how much of that rain will reach a particular house. In Matthew, Hampton Roads felt more impact than the forecast had expected, which shows how far the water can differ from the prediction.
In Suffolk the forecast for Matthew expected two to four inches of rain across the city. Rain that falls on saturated ground runs off rather than soaking in, so the actual water that reached a house depended on the ground, the drains and the roof, not only on the number in the forecast.
For a homeowner, the practical lesson is to read the house rather than the forecast. The readings from a crew show where the water went, and they are a better guide to the damage than any rainfall total published before the storm.
What should a homeowner outside a mapped zone do differently?
Do not assume the house is safe because the map does not show it at risk. Look at the entry points, keep the drains clear and know the cost of a flood in your own policy before a storm comes.
Walk the property after a heavy rain and note where water collects. Check the garage threshold, the crawl space vents, the back door and the lowest drain. Clearing debris from those points before a storm is a simple step that can keep water out.
Read your insurance policy, and ask your insurer whether water from a storm drain, a yard or a street is covered. Many standard homeowner policies generally exclude flood water from rivers and streets, so the answer matters before a storm, not after one.
What records help after a storm flood?
Photographs of the water and the damage, dated notes of the times the water appeared and receded, and the crew's readings and log are the most useful records. They help the insurer understand where the water came from and how far it went.
Take photographs before anything is moved, and again after each stage of the cleanup. Keep notes of the time the water first appeared, the rooms it reached and the source, if you can tell. Those notes are often the most useful part of the record later.
The crew's readings show how the water spread through the materials, and its log shows the drying stages. Keep those with the photographs, and ask the insurer which documents it needs to decide the claim.
What does the statewide finding mean for a single house?
The finding is a statewide figure, not a count for any one town, and it means that flooding outside the map happened often enough in Matthew to matter. It does not tell a homeowner whether a particular house will flood, but it does show that the map alone should not decide the question.
A homeowner in Suffolk or anywhere else in Virginia should not treat the statewide figure as a measure of their own risk. It is a sign of how the map and the ground can differ, and it is a reason to check the house as well as the map.
The crew responds to every call the same way, whatever the map says. It reads the house, the water and the routes it took, and it writes down what it finds, which is the only reliable answer to whether a particular house flooded.
What did the 2016 floods teach about recovery?
Recovery from Matthew showed that the cleanup takes longer than the flood, and that readings matter more than the surface. Homes dried to measured targets and recorded carefully were easier to rebuild and to claim for.
Flood recovery is slow because water that enters a building soaks into it. The surface can dry in days while the framing, the insulation and the subfloor take much longer. A homeowner who expected the house to be dry quickly was often disappointed, and that led to decisions made too soon, such as closing walls before the moisture had left.
The records mattered as well. Homes with dated photographs, drying logs and receipts were easier to assess than homes without them. The lesson for a homeowner today is to keep the records from the first day, even when the cleanup seems urgent and the paperwork seems secondary.
What can a homeowner do to reduce the next flood damage?
Simple steps before a storm can reduce the water that reaches a house and the damage it does. Clearing drains, checking the lowest openings and knowing where the shut-offs are all help.
Clear the storm drains and gutters near the house before the storm season, and check that the yard slopes away from the foundation. Keep the crawl space vents clear, and seal the garage threshold where it is practical to do so. Each of these steps keeps water further from the lowest parts of the house.
Know where the main water valve, the electrical panel and any gas shut-off are, and make sure they can be reached. Keep the numbers for the water line, a plumber and a roofer in one place. A homeowner who is prepared can act in the first hour, which is when much of the damage can be prevented.
Frequently asked questions
How many Virginia homes flooded in Matthew?
Virginia Emergency Management reports that roughly 2,000 homes were flooded statewide, and that many of them were outside the mapped floodplain. That is a statewide figure and not a count for any particular city.
Where can I see the official guidance?
The Virginia Emergency Management inland hurricane guide is published by the agency, and it describes the flooding that came with Matthew and the advice that followed. Read it for the official wording.
Does a flood map tell me my house is safe?
No. A flood map shows areas expected to flood in certain conditions and does not show every route water can take. A house outside the mapped area can still take water.
Should I buy flood insurance?
That is a decision for you and your insurer. Many standard homeowner policies generally exclude flood water, so read your policy and ask your insurer what it covers and what separate coverage is available.
What should I do if my house flooded outside the map?
Stay out of standing water, call a crew for the readings and the drying, and photograph the damage before anything is moved. Keep the records together for the insurer and ask for the decision in writing.
Can a crew tell me why my house flooded?
A crew can show where the water entered and how far it went, using readings and photographs. The reasons behind the flood, and whether a claim is covered, are for your insurer to decide under your policy.
Why did the forecast say two to four inches for Suffolk?
The forecast gave an expected rainfall total for the area. Rainfall forecasts are averages and estimates, and they do not show how much of the rain will run off, soak in or find a way into a particular house. The actual water depends on the ground, the drains and the roof.
Sources
This guide is general information for Suffolk (independent city) homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.