Floods

Introduction

Flooding is one of the most dangerous natural hazards worldwide and is responsible for more weather-related fatalities than almost any other event. Floods develop in many different forms: flash floods that sweep through urban streets, river systems that overflow after heavy rains, or coastal storm surge that pushes seawater inland.

Floods don’t discriminate. They affect rural communities, urban neighborhoods, and coastal regions alike. Understanding your flood risk, recognizing early warnings, and knowing how to respond can save lives. This guide consolidates guidance from the National Weather Service, Ready.gov, and international flood risk management organizations.

Hazard Types

Riverine (Fluvial) Flooding

When rivers or streams overflow due to prolonged rainfall or snowmelt. Floodwaters can spread across floodplains, inundating homes, farmland, and infrastructure.

Flash Floods

Sudden and violent flooding caused by intense rainfall, dam failures, or overwhelmed urban drainage systems. Flash floods can strike within minutes and are extremely dangerous due to their speed and force..

Coastal Flooding / Storm Surge

Seawater pushed ashore during major storms, hurricanes, or typhoons. Storm surge can rapidly inundate coastal areas, eroding land and destroying buildings.

Urban / Stormwater Flooding

Occurs when storm drains and sewers cannot keep up with heavy rainfall. Streets, basements, and underpasses flood quickly, often trapping vehicles.

Ice Jam & Glacial Flooding

Rivers can be blocked by ice, causing upstream flooding. In mountain regions, sudden glacial lake outbursts can release massive amounts of water downstream.

Levee / Dam Failure Flooding

When protective barriers fail, catastrophic flooding follows. These events release enormous volumes of water in a short time.

Isolation by Floodwaters

Communities or homes cut off by surrounding waters. Isolation creates deadly risks when people attempt to cross moving water.

Preparation

Before the event

Know your local flood risk zone through official maps and local authorities.
Sign up for official flood alerts and warnings.
Create a household flood plan: evacuation routes, shelter locations, family contacts.
Prepare a grab-and-go kit: medications, documents, clothing, flashlight, batteries, and first aid supplies.
Install sump pumps with battery backups; maintain gutters and drains.
Move valuables and electronics to higher ground when flooding is forecast.
Use sandbags or barriers to protect entry points in flood-prone areas.
Know how to safely turn off electricity, gas, and water in your home.

Checklist essentials

Trusted flood warning sources (local agencies, NWS, Ready.gov).

Emergency kit with three days of food, water, first aid, flashlight, and medications.

Waterproof bags for documents, valuables, and electronics.

Battery, solar, or crank-powered emergency radio.

Raised shelves/platforms for storage of valuables.

Emergency contact list, including nearby shelters and support networks.

During the event

Never walk, swim, or drive through floodwaters. “Turn Around, Don’t Drown.”
Move to higher ground immediately if you are in a low-lying area.
Follow evacuation orders promptly; don’t delay—roads and bridges may close quickly.
Avoid bridges and roads near rivers and streams during flooding.
Keep children and pets away from floodwaters; they are fast, deep, and contaminated.
Stay informed through radio, mobile alerts, or official websites.
If trapped, call for help. Signal from a roof or high window—never shelter in a flooded basement.

After the event

Return home only when authorities confirm it is safe.
Document all damages with photos and videos for insurance or relief claims.
Watch for hidden hazards: downed power lines, unstable structures, contaminated water, or displaced wildlife.
Discard all food and water that came in contact with floodwater.
Ventilate and disinfect affected spaces to prevent mold growth.
Wear protective gear—boots, gloves, masks—when cleaning.
Check on neighbors, especially the elderly and disabled.

Special Populations

Children

Never allow children to play in or near floodwaters. Risk of drowning, infections, and hidden debris is high.

Older Adults

Flood evacuations can be physically and emotionally stressful. Pre-plan support and transportation.

People with Disabilities / Medical Needs

Prepare for accessible evacuation and backup power for medical devices. Notify emergency services of specific needs in advance.

Businesses

Back up data, elevate assets, and develop continuity plans. Protect inventory with waterproofing measures.

Pets / Livestock

Include animals in evacuation planning. Bring food, leashes, cages, and vaccination records. Never leave pets behind in a flood zone.

Quick Reference Tables

Flood Stage Guidance

Flood Stage	Message	Key Actions
Watch	Flooding possible, stay alert	Monitor alerts, prepare kit and vehicle
Warning	Flooding imminent or underway	Evacuate or move to higher ground immediately
Evacuation	Leave when ordered/able	Secure home, bring pets, follow official routes
Post-Flood	Hazards remain	Wait for clearance, clean with caution

Key Reminder: Just 6 inches (15 cm) of moving water can knock an adult off their feet. 12 inches (30 cm) can sweep most vehicles away.

Additional notes/thoughts

Before flood season, ask yourself:

Am I living in a flood-prone area, and do I have flood insurance?
Can my family evacuate quickly—including children, seniors, and pets?
Are my documents, valuables, and medications secured in waterproof containers?
Do I have a reliable communication method if power and internet fail?
Have I taught and practiced the rule “Turn Around, Don’t Drown” with my family?

Floods develop rapidly and their impacts can last for months. Advance preparation and quick action are the most effective ways to protect life and property.