Fill your car gas tank, in case an evacuation notice is issued. Listen to local radio and TV stations for information and advice. If told to evacuate, do so as soon as possible. Killing walls of water can reach heights of 10 to 20 feet. You won't always have warning that these deadly, sudden floods are coming.
Flash floods can take only a few minutes to a few hours to develop.
You may have only seconds. This includes dips, low spots, canyons, washes, etc. Avoid already flooded and high velocity flow areas. Do not attempt to cross a flowing stream on foot where water is above you knees. Do not drive through flooded areas.