Flash Flood Safety at Home: Basements, Streets and Floodwater

In a flash flood, the safest moves are simple: get to higher ground early, and never walk or drive into floodwater. If you live in a basement unit, go to a higher floor as soon as heavy rain is on the way, before any water comes in.

Floods don't feel like a drowning risk the way a lake or pool does. But moving water is powerful, it hides what is underneath, and it can rise fast indoors.

Why floodwater is a drowning hazard

6 inches

The National Weather Service (NWS) explains how little water it takes:

• 6 inches of fast-moving flood water can knock over an adult (opens in a new tab).
• 12 inches of rushing water can carry away most cars (opens in a new tab), and 2 feet can carry away SUVs and trucks.
• The road you can't see may have collapsed under that water (opens in a new tab).

NYC Emergency Management says flash flooding is the number one cause of deaths associated with thunderstorms, claiming more than 140 lives each year in the United States (opens in a new tab), and that it has become more frequent and more severe in recent years.

Basement apartments: move up early

Water can fill a below-ground room quickly, and the stairs or door may become the only way out. That is why the advice for basement residents is to act before the water arrives.

• Move up when heavy rain is coming. NYC Emergency Management says: if you live in a basement apartment, go to a higher floor when it rains. Do not wait for water to enter your unit (opens in a new tab).
• Know your way out. Practice the safest route from your home to safe, high ground (opens in a new tab) in case you have to leave.
• Line up a place to go. Agree in advance with an upstairs neighbor, friend or relative that you can come to them during a storm warning.
• Keep a Go Bag ready. NYC Emergency Management suggests a Go Bag you can grab in case you need to leave your home in a hurry (opens in a new tab).
• Don't rely on flood maps alone. The city says residents should not use flood zones to determine the need to evacuate (opens in a new tab). Street and basement flooding can happen far from the coast.

During a flood, NYC Emergency Management also warns not to use the phone or any electrical appliance connected to the building's electrical wiring (opens in a new tab), and to always stay away from downed power lines (opens in a new tab). A charged mobile phone is the safest way to call for help.

Never walk or drive into floodwater

The NWS campaign "Turn Around Don't Drown" exists because over half of all flood-related drownings occur when a vehicle is driven into hazardous flood water (opens in a new tab). The next most common is walking into or near flood waters (opens in a new tab).

• Driving: Never drive around barriers or through water covering a road. NYC Emergency Management notes that six inches of water will reach the bottom of most passenger cars, causing loss of control and possible stalling (opens in a new tab). Turn around and find another way.
• Walking: The city says no one should ever walk or drive through flooded streets, stairwells, subway stations, or underpasses (opens in a new tab).
• Children: Floodwater can look like a big puddle to a child. Keep children out of it, and away from fast-moving water in streets, streams and rivers. Our river safety guide explains why moving water is so strong.

The NWS sums it up: it is never safe to drive or walk into flood waters (opens in a new tab).

Alerts to sign up for

Warnings give you time to move up before water arrives.

• Notify NYC. The city's free emergency alert service. NYC Emergency Management strongly encourages basement residents to join its Notify NYC Basement Alert Group: visit nyc.gov/notify and select the option for basement apartments (opens in a new tab). You can also register through the free app or by calling 311 (opens in a new tab).
• Phone alerts. Keep emergency alerts turned on on your phone, and act on any flash flood warning for your area right away.
• Text-to-911. In New York City you can text 911 if you can't safely speak, but the city says to always call 911 if you can and text 911 only if you can't (opens in a new tab).

Make a flood plan with your household

Put flooding in your family water safety plan, next to pools and lakes. Agree on:

• When you move up: as soon as a flash flood warning or heavy rain alert arrives.
• Where you go: an upstairs neighbor, relative or nearby shelter.
• How you get there: the route to high ground, practiced once in daylight.
• Who helps whom: who carries the baby, who helps an older relative, who brings the pets.
• What you take: the Go Bag, phone chargers, medicines and important papers.
• How you reach each other: one contact person outside the area everyone can call or text.
• Who calls 911, and what address to give.

If someone in your home speaks limited English, make sure they can get alerts and know the plan. Our guide for new immigrant families has more on water safety for families new to the U.S. For what to say when you call, see calling 911 near water.

What you can do today

1. Sign up for Notify NYC (or your local alert service), and choose the basement option if it applies.
2. Talk to an upstairs neighbor or relative about a place to go during storms.
3. Pack a Go Bag and put it by the door.
4. Add flooding to your plan with the Family water safety plan tool, and post your address on the Water Emergency Action Plan.
5. Teach "Turn around, don't drown" to every driver and every child in your home.