A flood is the inundation of normally dry land resulting from the rising and overflowing of a body of water. Floods can develop slowly over the course of several days or can develop quickly. Localized flooding (also known as urban flooding) can occur when water collects or pools in an area where water is not normally present, such as an area that has a blocked storm water drain. 

What are King Tides, and When Do They Occur?

King tides are higher-than-usual tides which can produce local "sunny day" flooding, or flooding which occurs even though there is no rain. The National Oceanic and Atmospheric Administration (NOAA) publishes predictions of high tide heights here, which can be used to anticipate days on which king tides may occur. Read more on king tides below.

What Does the Term '100-year' Flood Mean?

A 100-year flood (also known as a base flood) is a term that describes a significant flood event that statistically has a 1% chance of occurring in any given year. Despite its name, it is not a flood that occurs every 100 years. A 100-year flood can occur one year, and then again the following year. 

Flood Preparedness

Floods are the most common and widespread of all natural disasters.  If you live in an area where floods occur, you should know the following:


  • Plan for evacuation including where you are going to go and the route you will follow.
  • Prepare your home for a flood. Call your local building department or office of emergency management for information. (click here for seven ways to protect your home from flooding)
  • Purchase flood insurance. Homeowner's insurance doesn't cover floods.
  • Elevate your utilities or HVAC systems.
  • Install a sewage water backstop.
  • Keep all insurance policies and a list of valuable items in a safe place.
  • Take photos or a videotape of the valuables you keep in your home.
  • Listen to your radio or television for reports of flood danger.
  • Keep your car's tank filled with gas.


  • Do not try to walk or drive through flooded areas. Water can be deeper than it appears, and water levels rise quickly. Follow official emergency evacuation routes.  If your car stalls in floodwater, get out quickly and move to higher ground.
  • Stay away from moving water; moving water six inches deep can sweep you off your feet. Cars are easily swept away in just two feet of water.
  • Stay away from disaster areas unless authorities ask for volunteers.
  • Stay away from downed power lines.
  • If your home is flooded, turn the utilities off until emergency officials tell you it is safe to turn them on. Do not pump the basement out until floodwater recedes.  Avoid weakened floors, walls and rooftops.
  • Wash your hands frequently with soap and clean water if you come in contact with floodwaters.


  • Wear gloves and boots when cleaning up.
  • Open all doors and windows. Use fans if possible to air out the building.
  • Wash all clothes and linens in hot water.
  • Discard mattresses and stuffed furniture; they can't be adequately cleaned.
  • Wash dirt and mud from walls, counters and hard surfaced floors with soap and water. Disinfect by wiping surfaces with a solution of one cup bleach per gallon of water.
  • Discard all food that has come into contact with floodwater. Canned food is alright, but thoroughly wash the can before opening.
  • If your well is flooded, your tap water is probably unsafe.  If you have public water, the health department will let you know - through radio and television - if your water is not safe to drink.  Until your water is safe, use clean bottled water.
  • Learn how to purify water. If you have a well, learn how to decontaminate it.
  • Do not use your septic system when water is standing on the surrounding ground. The ground below will not absorb water from sinks or toilets.  When the soil has dried, it is probably safe to again use your septic system.  To be sure, contact your local health department. 
  • When floodwaters have receded, watch out for weakened road surfaces.
  • Flood Cleanup Guide

Learn more from the NFIP through FEMA.

Prepare Before a King Tide

  • Have a plan in place to move your vehicles to higher ground before a king tide event.
  • Keep sandbags on hand.
  • Review your flood insurance policy or considering getting one.
  • Make a flood safety plan.
  • Identify alternate evacuation routes.


Protect Yourself During or After a King Tide

  • Do not walk through flood water. This can be a health and safety issue.
  • Do not drive through flooded water.
  • Remove your trash and recycle bins from the curb.