Prepare

Again, it is what you do before, that dictates how you react during

If flash flooding is a potential risk in your area, you need to monitor the potential signs, obviously heavy rains.
If your area has had recent fires, even slight rain can increase the risk of flooding, so stay alert.
Learn your evacuation routes and practice them.
Setup a shelter plan, such as where to go, and how to respond.
Keep an emergency kit ready to go. Include a 3 day supply of food and water, radio, flashlight, batteries, and medicines.
Keep your important documents in a water proof container, or keep digital copies on a thumbdrive.
If possible, move your valuables to higher levels in your house, apartment or workplace.
Before flooding hits, unplug your major appliances or shutoff the main circuit breaker.

Survive

Remember your plan & stay calm

Remember your evacuation route to your shelter, use it.
Do NOT walk, swim or drive through flood waters.
TURN AROUND. DONT DROWN!
Do NOT attempt to cross a bridge that is over fast moving water, it can easily be washed away, with you.
If you get stuck in rising water, stay inside your car or get on the roof.
NEVER climb into your attic, you will be stuck with nowhere to go.

Recover

Tread on the side of caution afterwards

Only go back home after authorities have given the all clear.
If your house is flooded, be aware that there may be snakes and other animals inside.
Do NOT touch electrical equipment if it is wet or in standing water. Remember we said to unplug and shutoff applicance and the main circuit breaker before the flood.
Do NOT wade in floodwater. It can be contaminated, full of debris, and in some cases, electrically charged by downed power lines.