Flooding risk in Mississippi

Flooding in Mississippi: A State Shaped by Water

Flooding is one of the most frequent and widespread natural hazards in Mississippi. The state borders the Gulf of Mexico to the south and the Mississippi River to the west, and it is crossed by dozens of smaller river systems, including the Pearl, Pascagoula, Tombigbee, Yazoo, Big Black, Leaf and Chickasawhay rivers. Heavy tropical rainfall, slow-moving thunderstorms and backwater from larger rivers all push water into places that may rarely see it. Because so much of the state is low-lying, flood risk is not limited to the coast or to homes built directly on a riverbank.

Where flooding is most likely

• The Gulf Coast — Hancock, Harrison and Jackson counties. Hurricanes and tropical storms bring storm surge along the shoreline and heavy rain well inland. When surge and rainfall happen at the same time, water can back up into coastal creeks and drainage systems that normally carry it away.
• The Mississippi River valley and the Delta. River flooding along the state's western border is often slow to develop and slow to drain, lasting days or weeks after heavy rain falls far upstream. Backwater flooding can reach land miles from the river channel.
• The Pearl River basin and the Jackson area. The Pearl has a long record of flooding in and around Jackson, including the 1979 Easter flood. Low-lying neighborhoods in Hinds, Rankin and Madison counties can flood from river overflow, heavy local rain, or both.
• North, central and northeast Mississippi. Steep hills and quickly developing areas make flash flooding a concern along small creeks, in urban drainage ways and at low-water crossings.

When flooding happens

Mississippi's flood risk shifts with the seasons. The Atlantic hurricane season runs from June 1 through November 30, with the greatest tropical threat generally from August through October. Winter and early spring storms can saturate the ground and hold river levels high for weeks, while summer thunderstorms can produce flash flooding almost anywhere with very little warning. Flash floods are especially dangerous: the National Weather Service notes that roughly half of all flood-related drownings happen when people drive into flooded roads, which is why "Turn Around, Don't Drown" is repeated so often.

How Flooding Affects Homes

Water damage in a home is rarely just a wet floor. Floodwater is often muddy, contaminated and under pressure, and it can reach parts of a house that are expensive to repair.

• Structure and finishes. Drywall, insulation, flooring, cabinetry and trim below the flood line usually have to be removed and replaced.
• Utilities and mechanical systems. Electrical panels, outlets, water heaters, furnaces and HVAC equipment near ground level are frequently destroyed.
• Foundations and crawl spaces. Prolonged saturation can lead to foundation movement, and trapped moisture supports rot and mold.
• Mold. The CDC and FEMA advise drying a home within 24 to 48 hours, because mold can begin growing on wet materials quickly.
• Sewer backup. During heavy rain, storm and sanitary systems can back up into basements and ground-floor drains.

Insurance is the part many homeowners miss. Standard homeowners and renters policies generally do not cover flood damage. Coverage comes from a separate flood policy, either through the National Flood Insurance Program or a private insurer. NFIP policies typically have a 30-day waiting period before coverage begins, so a policy bought as a storm approaches will not help. Mortgage lenders require flood insurance when a home sits in a Special Flood Hazard Area on FEMA's flood maps, but FEMA notes that a significant share of flood claims come from properties outside those high-risk zones.

After a flood, repairs may also trigger local floodplain rules. If damage equals or exceeds 50 percent of a home's pre-flood market value, many communities classify it as "substantially damaged" and require the building to meet current floodplain standards — which can mean elevating the structure above the base flood elevation.

How to Prepare Your Home for Flooding

1. Find out your flood zone. Look up your address on the FEMA Flood Map Service Center and confirm details with your city or county floodplain administrator.
2. Buy flood insurance before you need it — and remember the 30-day waiting period.
3. Elevate what you can. Move the electrical panel, outlets, water heater, furnace and HVAC equipment above the expected flood level. Elevating utilities is often cheaper than replacing them.
4. Manage water around the house. Keep gutters and downspouts clear, direct downspouts well away from the foundation, and grade soil so it slopes away from the home.
5. Install a sump pump with a battery backup in basements and crawl spaces, and consider a backflow valve to stop sewage from backing up into the house.
6. Consider flood vents or an open crawl space design that lets water pass through instead of pushing against the foundation, and seal cracks in walls and floors.
7. Protect what is inside. Store documents, photos and valuables above the expected flood level or in waterproof containers, and keep digital copies.
8. Know your plan. Sign up for local alerts, keep a NOAA weather radio, and identify safe routes out of your neighborhood — and never drive through flooded roads.

Frequently Asked Questions

Do I need flood insurance in Mississippi?

If you have a federally backed mortgage on a home in a Special Flood Hazard Area, your lender will require flood insurance. Even when it is not required, it is worth pricing: flooding in Mississippi also happens outside mapped high-risk zones, from heavy rain, small creeks and drainage problems. Standard homeowners policies exclude flood damage, so the only way to be covered is a separate NFIP or private flood policy.

Is flooding only a coastal problem in Mississippi?

No. Coastal counties face storm surge and tropical rainfall, but river flooding along the Mississippi River and the Pearl River, backwater flooding in the Delta, and flash flooding in the hills of north and central Mississippi all cause serious damage well inland. A large share of the state's repeat flood damage happens far from the Gulf.

What should I do when a flood watch or warning is issued?

A watch means flooding is possible; a warning means it is happening or imminent. Move to higher ground, avoid driving or walking through floodwater, and follow instructions from the Mississippi Emergency Management Agency and local officials. Review the National Weather Service flood safety guidance before the next storm so you already know what to do.

Official Resources

• Mississippi Emergency Management Agency (MEMA)
• FEMA Flood Map Service Center
• National Flood Insurance Program — FloodSmart
• NOAA National Weather Service — Flood Safety