Understanding flash flood warnings
Flash floods develop quickly, often within minutes to a few hours of intense rainfall. Unlike river flooding, which builds over days, flash floods give you very little time to react. That is why the first 10 minutes matter more than any other disaster scenario.
There are two main alert types. A Flash Flood Watch means conditions are right for flooding. A Flash Flood Warning means flooding is happening or imminent. If you receive a Warning on your phone, treat it as urgent. Do not wait to see the water before acting.
Urban areas are especially vulnerable because concrete and asphalt prevent water absorption. A storm that would be harmless in a forested area can flood a city street in minutes. Underpasses, parking garages, and basement apartments are the first to fill.
Minute 0 to 2: choose higher ground
Do not wait to confirm exact water depth. Move away from drainage channels, basements, underpasses, and low roads. If you are in a vehicle, reroute before roads disappear. Water can rise faster than you can drive out of its path.
If you are on foot, move to the nearest elevated ground. Avoid walking through water deeper than your ankles. Moving water at ankle depth can still sweep you off your feet, especially if the ground underneath is slippery or uneven.
If you are in a building, move to an upper floor. Do not use elevators if water is entering the structure. Take your phone, a flashlight, and your emergency kit with you.
Minute 2 to 5: protect essentials
Put phone, charger, medicine, IDs, cash, and keys into a dry bag or sealed plastic pouch. Text your location to one trusted person before networks get crowded. Phone calls may fail when towers are overloaded, but text messages often get through.
If you have time, move valuables and electronics off the floor. Unplug non-essential electronics if you can do so safely. Do not touch electrical panels or appliances while standing in water.
Grab shoes that you can walk long distances in. Floodwater contains debris, bacteria, and sharp objects. Barefoot evacuation leads to injuries that become infected quickly.
Minute 5 to 10: avoid the fatal mistake
Never drive through water covering the road. The road may be washed out underneath, and moving water can push vehicles faster than most drivers expect. As little as 15 cm of moving water can knock an adult down, and 30 cm can move a car. At 60 cm, most vehicles will float.
If your vehicle stalls in water, abandon it immediately and move to higher ground. Do not stay in the car hoping the water will recede. People die in stalled vehicles every year because they waited too long to leave.
If water is already at your doors and rising, exit through a window if doors will not open. Water pressure against a car door makes it nearly impossible to open once water reaches door handle height.
After the first 10 minutes
Once you are on safe ground, stay there. Do not return to check on property until officials confirm the area is safe. Floodwater can recede and then rise again as additional rainfall arrives downstream.
Avoid walking or driving through floodwater on the return trip. Water depth is deceptive, and floodwater often hides open manholes, washed-out road sections, and downed power lines. Assume all floodwater is contaminated with sewage and chemicals.
Document damage with photos before cleanup begins. This will be needed for insurance claims. Do not turn on electricity or gas until a professional has inspected the system.
Why most flash flood deaths involve vehicles
Over half of flash flood deaths in the United States are vehicle-related. The reason is simple: people underestimate water depth and overestimate vehicle capability. SUVs and trucks are not safer. Their larger surface area makes them more likely to float.
The Turn Around Dont Drown campaign was created specifically because of this pattern. The message is simple. If you cannot see the road surface through the water, turn around. The six seconds you save by driving through are not worth your life.
Nighttime is the most dangerous time. Water depth and road conditions are nearly impossible to judge in the dark. If a flash flood warning is active, avoid all non-essential driving until daylight.
FAQ
Is it safe to drive through shallow floodwater?
No. Shallow-looking water can hide road damage or strong current. As little as 30 cm of moving water can move a vehicle. Turn around and find another route.
Where should I go during a flash flood warning?
Move to higher ground, away from rivers, channels, underpasses, and basements. Follow local evacuation instructions. If you are in a vehicle, do not drive through water covering the road.
What should I keep dry during a flood watch?
Keep IDs, medication, cash, phone, charger, power bank, and basic first aid in a waterproof bag near the exit. Add important documents like insurance policies and medical records if time allows.
How fast does a flash flood happen?
Flash floods can develop in minutes to a few hours. Urban flash floods can turn a dry street into a river in under 30 minutes during intense rainfall.
What do I do if my car stalls in floodwater?
Abandon the vehicle immediately and move to higher ground. Do not wait for the water to recede. If doors will not open due to water pressure, exit through a window.