Jefferson County obtains flood warning information from the National Weather Service. Information is received 24 hours a day, 7 days a week by JeffCom (911 Communications). Flood warnings are disseminated via radio (710AM), and other communication methods.
For up to date flood warnings and weather information, you can also visit the NOAA website.
You may wish to purchase a weather alert radio that will sound in your home in case of a weather emergency, including floods. The radios are inexpensive and available at most hardware stores.
If case a flood warning is issued and you need to evacuate, keep your car filled with gas.
If you know a flood is coming, you should shut off the main gas and electricity switch (forget about the food in your fridge - it will be contaminated anyway), and move your valuables upstairs. It is unlikely that you will get much warning, so a detailed checklist prepared in advance would help ensure that you don't forget anything.